Multi-component copolymer, rubber composition, crosslinked rubber composition and rubber article

ABSTRACT

Provided is a multi-component copolymer capable of improving the rollability of a rubber composition while having excellent low heat generating property. The multi-component copolymer comprises conjugated diene units, non-conjugated olefin units and aromatic vinyl units, wherein: a ratio among all of the aromatic vinyl units of at least one aromatic vinyl unit existing in amorphous parts inclusive of the conjugated diene units is less than 50%.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2016/004543 filed Oct. 11, 2016, claiming priority based onJapanese Patent Application No. 2015-204978 filed Oct. 16, 2015.

TECHNICAL FIELD

This disclosure relates to a multi-component copolymer, a rubbercomposition, a crosslinked rubber composition and a rubber article.

BACKGROUND

Generally, rubber compositions used in manufacture of rubber articlessuch as tires, conveyor belts, anti-vibration rubbers and seismicisolation rubbers are required to have excellent durability,processability (in particular, rollability), low heat generatingproperty, etc. In such situation, various rubber components and rubbercompositions have been developed.

For example, from the viewpoint of improving the durability, PTL1discloses a copolymer of a conjugated diene compound and anon-conjugated olefin in which conjugated diene parts (parts derivedfrom a conjugated diene compound) have a cis-1,4 bond content of greaterthan 70.5 mol % and a non-conjugated olefin is contained in an amount of10 mol % or more, and discloses that this copolymer is used formanufacturing rubber having good durability, such as crack growthresistance.

CITATION LIST Patent Literature

PTL1: WO2012/014455A1

SUMMARY Technical Problem

Such copolymer has conjugated diene parts which have a comparativelyhigh cis-1,4 bond content, and thus is regarded as having excellent lowheat generating property. On the other hand, such copolymer is abicopolymer polymerizing one conjugated diene compound and onenon-conjugated olefin compound, and thus tends to have a large chainlength of parts of continuous units derived singly from thenon-conjugated olefin compound, in particular, a chain length of partsof continuous units derived from ethylene in the case of using ethylene,resulting in increase in crystallinity. Such copolymer can be furtherimproved by avoiding gigantic crystal in the copolymer as much aspossible, thereby further improving the rollability of a rubbercomposition using this copolymer (enabling the rubber composition to bewound well to a roll).

Regarding the aforementioned problems of the conventional art, it thuswound be helpful to provide a multi-component copolymer capable ofimproving the rollability of a rubber composition while having excellentlow heat generating property. Moreover, it would be helpful to provide arubber composition having excellent low heat generating property androllability. Furthermore, it would be helpful to provide a crosslinkedrubber composition and a rubber article using the aforementioned rubbercomposition, which is easy to manufacture and has excellent low heatgenerating property.

Solution to Problem

As a result of intensive study, we accomplished this disclosure bydiscovering that a copolymer having at least three units in a specificform contributes to improvement of the rollability of a rubbercomposition while having excellent low heat generating property.

In order to beneficially solve the aforementioned problem, thisdisclosure is a multi-component copolymer comprising conjugated dieneunits, non-conjugated olefin units and aromatic vinyl units, wherein: aratio among all of the aromatic vinyl units of at least one aromaticvinyl unit existing in amorphous parts inclusive of the conjugated dieneunits is less than 50%.

In the present Specification, the term “conjugated diene unit” refers toa unit in the copolymer equivalent to a unit derived from a conjugateddiene compound; the term “non-conjugated olefin unit” refers to a unitin the copolymer equivalent to a unit derived from a non-conjugatedolefin compound; and the term “aromatic vinyl unit” refers to a unit inthe copolymer equivalent to a unit derived from an aromatic vinylcompound.

Moreover, in the present Specification, the term “conjugated dienecompound” refers to conjugated-system diene compound; the term“non-conjugated olefin compound” refers to a non-conjugated-systemaliphatic unsaturated hydrocarbon compound having one or morecarbon-carbon double bonds; and the term “aromatic vinyl compound”refers to an aromatic compound substituted with at least a vinyl group.Moreover, the “aromatic vinyl compound” is not included in theconjugated diene compound.

Furthermore, in the present Specification, the term “multi-componentcopolymer” refers to a copolymer obtained by polymerizing monomers ofthree types or more.

The rubber composition of this disclosure comprises the aforementionedmulti-component copolymer of this disclosure.

The crosslinked rubber composition of this disclosure is a crosslinkedproduct of the aforementioned of this disclosure rubber composition.

The rubber article of this disclosure uses the aforementionedcrosslinked rubber composition of this disclosure.

Advantageous Effect

According to this disclosure, it is possible to provide amulti-component copolymer capable of improving the rollability of arubber composition while having excellent low heat generating property.Moreover, according to this disclosure, it is possible to provide arubber composition having excellent low heat generating property androllability. Furthermore, according to this disclosure, it is possibleto provide a crosslinked rubber composition and a rubber article usingthe aforementioned rubber composition, which are easy to manufacture andhave excellent low heat generating property.

DETAILED DESCRIPTION

In below, the method of this disclosure is described in detail withreference to embodiments thereof.

(Multi-Component Copolymer)

The multi-component copolymer of this disclosure is principallycharacterized by comprising conjugated diene units, non-conjugatedolefin units and aromatic vinyl units. Namely, different from acopolymer of a conjugated diene compound and a non-conjugated olefin asconventional art, the copolymer of this disclosure has aromatic vinylunits in addition to conjugated diene units and non-conjugated olefinunits. Further, in the copolymer of this disclosure, a ratio among allof the aromatic vinyl units of at least one aromatic vinyl unit existingin amorphous parts inclusive of the conjugated diene units is less than50%. In other words, in the copolymer of this disclosure, the amount ofthe aromatic vinyl units introduced to parts linking mainly theconjugated diene units is suppressed to less than 50% of all of thearomatic vinyl units. Therefore, the copolymer of this disclosure isregarded as suppressing excessive rise of a glass-transition temperature(Tg), and thereby maintaining excellent low heat generating property. Onthe other hand, in the copolymer of this disclosure, since 50% or moreof all of the aromatic vinyl units are introduced to crystalline partsor amorphous parts exclusive of the conjugated diene units, it isregarded that a length of parts linking mainly the non-conjugated olefinunits is shortened, and thus generation excessively large crystal issuppressed, which improves the rollability.

Moreover, the multi-component copolymer of this disclosure, as describedin its producing method in the following, can be synthesized in onereaction container, i.e., via one-pot synthesis, and thus can beproduced with a simplified process.

Note that in the present Specification, the “crystalline parts” of themulti-component copolymer refer to parts corresponding to a componentobtained after ozonolysis of the multi-component copolymer, and the“amorphous parts” of the multi-component copolymer refer to parts otherthan the aforementioned crystalline parts.

The multi-component copolymer of this disclosure is polymerized by usinga conjugated diene compound as a monomer, and thus has bettercrosslinking property as compared to, e.g., a copolymer polymerizedwithout using a conjugated diene compound such as a well-knownethylene-propylene-non-conjugated diene copolymer (EPDM). Therefore, themulticomponent copolymer of this disclosure also has an advantage offurther improving mechanical properties of rubber compositions andrubber articles produced by using the disclosed multicomponentcopolymer.

The conjugated diene units in the multi-component copolymer of thisdisclosure are normally units derived from a conjugated diene compoundas a monomer, where the conjugated diene compound preferably has acarbon number of 4 to 8. Specific examples of such conjugated dienecompound include 1,3-butadiene, isoprene, 1,3-pentadiene, and2,3-dimethyl-1,3-butadiene. The conjugated diene compounds may be usedsingly or in a combination of two or more. From the viewpoint ofeffectively improving a durability of a rubber composition or a rubberarticle such as tires using the multi-component copolymer, theconjugated diene compound as a monomer from which the conjugated dieneunits in the multi-component copolymer of this disclosure are derivedpreferably contains 1,3-butadiene and/or isoprene, more preferablyconsists exclusively of 1,3-butadiene and/or isoprene, even morepreferably consists exclusively of 1,3-butadiene. In other words, theconjugated diene units in the multi-component copolymer of thisdisclosure preferably include 1,3-butadiene units and/or isoprene units,more preferably consist exclusively of 1,3-butadiene units and/orisoprene units, even more preferably consist exclusively of1,3-butadiene units.

In the multi-component copolymer of this disclosure, it is preferablethat a content of the conjugated diene units is 15 mol % or more. Bysetting the content of the conjugated diene units to 15 mol % or more,the multi-component copolymer becomes capable of serving uniformly as anelastomer and achieving a higher durability. From the same viewpoint, inthe multi-component copolymer of this disclosure, the content of theconjugated diene units is more preferably 20 mol % or more, even morepreferably 25 mol % or more.

On the other hand, in the multi-component copolymer of this disclosure,it is preferable that the content of the conjugated diene units is 60mol % or less. By setting the content of the conjugated diene units to60 mol % or less, it is possible to sufficiently obtain an effect ofhaving units other than the conjugated diene units. From the sameviewpoint, in the multi-component copolymer of this disclosure, thecontent of the conjugated diene units is more preferably 55 mol % orless, even more preferably 50 mol % or less.

Here, in the multi-component copolymer of this disclosure, a cis-1,4bond content among all of the conjugated diene units is preferably 50%or more, more preferably 70% or more, even more preferably 80% or more,particularly preferably 90% or more. By setting the cis-1,4 bond contentamong all of the conjugated diene units to 50% or more, since aglass-transition temperature (Tg) is lowered consciously, it is possibleto effectively improve the durability (crack growth resistance, wearresistance, etc.) and the low heat generating property of themulti-component copolymer.

On the other hand, a vinyl bond (1,2-vinyl bond, 3,4-vinyl bond, etc.)content among all of the conjugated diene units is preferably 50% orless, more preferably 30% or less, even more preferably 15% or less,further more preferably 10% or less, particularly preferably 6% or less.Moreover, a trans-1,4 bond content among all of the conjugated dieneunits is preferably 30% or less, more preferably 15% or less, even morepreferably 10% or less.

The non-conjugated olefin units in the multi-component copolymer of thisdisclosure are normally units derived from a non-conjugated olefincompound as a monomer, where the non-conjugated olefin compoundpreferably has a carbon number of 2 to 10. Specific examples of suchnon-conjugated olefin compound include: α-olefins such as ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene; andhetero atom substituted alkene compounds such as vinyl pivalate,1-phenylthioethene and N-vinylpyrrolidone. The non-conjugated olefincompounds may be used singly or in a combination of two or more. Fromthe viewpoint of generating a crystal capable of functioning well as areinforcing member, the non-conjugated olefin compound as a monomer fromwhich the non-conjugated olefin units in the multi-component copolymerof this disclosure are derived is preferably an acyclic non-conjugatedolefin compound, where the acyclic non-conjugated olefin compound ismore preferably an α-olefin, even more preferably consists exclusivelyof one or more selected from ethylene, propylene or 1-butene, andparticularly preferably consists exclusively of ethylene. In otherwords, the non-conjugated olefin units in the multi-component copolymerof this disclosure are preferably acyclic non-conjugated olefin units,where the acyclic non-conjugated olefin units are more preferablyα-olefin units, even more preferably consist exclusively of one or moreselected from ethylene units, propylene units or 1-butene units, andparticularly preferably consist exclusively of ethylene units.

In the multi-component copolymer of this disclosure, it is preferablethat a content of the non-conjugated olefin units is 25 mol % or more.By setting the content of the non-conjugated olefin units to 25 mol % ormore, a crystal is generated at a lowest amount in the multi-componentcopolymer, which improves the durability such as crack growthresistance, etc. From the same viewpoint, in the multi-componentcopolymer of this disclosure, the content of the non-conjugated olefinunits is more preferably 30 mol % or more, even more preferably 40 mol %or more.

On the other hand, in the multi-component copolymer of this disclosure,it is preferable that the content of the non-conjugated olefin units is80 mol % or less. By setting the content of the non-conjugated olefinunits to 80 mol % or less, it is possible to sufficiently obtain theeffect of having units other than the non-conjugated olefin units. Fromthe same viewpoint, in the multi-component copolymer of this disclosure,the content of the non-conjugated olefin units is more preferably 70 mol% or less, even more preferably 60 mol % or less.

The aromatic vinyl units in the multi-component copolymer of thisdisclosure are normally units derived from an aromatic vinyl compound asa monomer, where the aromatic vinyl compound preferably has a carbonnumber of 8 to 10. Examples of such aromatic vinyl compound includestyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene,o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene and p-ethylstyrene.The aromatic vinyl compounds may be used singly or in a combination oftwo or more. From the viewpoint of effectively suppressing generation ofan excessively large crystal to thereby improve the rollability, thearomatic vinyl compound as a monomer from which the aromatic vinyl unitsin the multi-component copolymer of this disclosure are derivedpreferably contains styrene, more preferably consists exclusively ofstyrene. In other words, the aromatic vinyl units in the multi-componentcopolymer of this disclosure preferably include styrene units, morepreferably consist exclusively of styrene units.

In the multi-component copolymer of this disclosure, it is preferablethat a content of the aromatic vinyl units is 2 mol % or more. Bysetting the content of the aromatic vinyl units to 2 mol % or more, itis possible to introduce the aromatic vinyl units at a sufficient amountto the crystalline parts or the amorphous parts exclusive of theconjugated diene units. From the same viewpoint, in the multi-componentcopolymer of this disclosure, the content of the aromatic vinyl units ismore preferably 5 mol % or more, even more preferably 10 mol % or more.

On the other hand, in the multi-component copolymer of this disclosure,it is preferable that the content of the aromatic vinyl units is 30 mol% or less. By setting the content of the aromatic vinyl units to 30 mol% or less, it is possible to sufficiently obtain the effect of havingunits other than the aromatic vinyl units. From the same viewpoint, inthe multi-component copolymer of this disclosure, the content of thearomatic vinyl units is more preferably 20 mol % or less, even morepreferably 15 mol % or less.

Note that the multi-component copolymer of this disclosure may have anyunit other than the aforementioned conjugated diene units,non-conjugated olefin units and aromatic vinyl units. However, from theviewpoint of obtaining the desired effects of this disclosure, a contentof any unit other than the conjugated diene units, the non-conjugatedolefin units and the aromatic vinyl units in the multi-componentcopolymer of this disclosure is more preferably 0 mol % (i.e., do notcontain other units).

The number of types of monomers from which the multi-component copolymerof this disclosure is derived is not specifically limited, as long asthe multi-component copolymer has the conjugated diene units, thenon-conjugated olefin units and the aromatic vinyl units. However, fromthe viewpoint of obtaining better low heat generating property androllability of the rubber composition, it is preferable that themulti-component copolymer of this disclosure is a polymer obtained byperforming polymerization at least using as monomers one conjugateddiene compound, one non-conjugated olefin compound and one aromaticvinyl compound. In other words, it is preferable that themulti-component copolymer of this disclosure is a multi-componentcopolymer having one type of conjugated diene units, one type ofnon-conjugated olefin units and one type of aromatic vinyl units.Furthermore, from the same viewpoint, the multi-component copolymer ofthis disclosure is more preferably a tricopolymer consisting exclusivelyof one type of conjugated diene units, one type of non-conjugated olefinunits and one type of aromatic vinyl units, even more preferably atricopolymer consisting exclusively of 1,3-butadiene units, ethyleneunits and styrene units. In this connection, the “one type of conjugateddiene units” is inclusive of conjugated diene units of different bondingmodes (cis-1,4 bond, trans-1,4 bond, 1,2-vinyl bond, etc.).

Here, as described above, in order to improve the low heat generatingproperty and the rollability of a rubber composition, in themulti-component copolymer of this disclosure, the ratio among all of thearomatic vinyl units of at least one aromatic vinyl unit existing inamorphous parts inclusive of the conjugated diene units is necessarilyless than 50%, while from the viewpoint of further improving the lowheat generating property and the rollability of a rubber composition,this ratio is preferably less than 40 mol %, more preferably less than30 mol %. Moreover, a lower limit of the ratio is not specificallylimited, while from the viewpoint of appropriately raising theglass-transition temperature to thereby improve the wet performance (thegripping performance on wet surface), etc., 5 mol % or more ispreferable, and 10 mol % or more is more preferable.

Note that the ratio among all of the aromatic vinyl units of at leastone aromatic vinyl unit existing in amorphous parts inclusive of theconjugated diene units may be obtained by obtaining a ratio (A) of thenon-conjugated olefin units and the aromatic vinyl units in themulti-component copolymer from an integration ratio of the ¹H-NMRspectrum and the ¹³C-NMR spectrum, then ozonolyzing the diene partscontained in the multi-component copolymer, obtaining a ratio (B) of thenon-conjugated olefin units and the aromatic vinyl units in the entireobtained component exclusive of the diene parts (the componentconsisting of the non-conjugated olefin units and/or the aromatic vinylunits) from an integration ratio of the ¹H-NMR spectrum and the ¹³C-NMRspectrum, and calculating by using the ratio (A) and the ratio (B).Specifically, the measurement may be performed with the method asdescribed in Examples of the present Specification.

In the multi-component copolymer of this disclosure, it is preferablethat the main chain consists exclusively of an acyclic structure. A mainchain consisting exclusively of an acyclic structure is capable ofsuppressing deterioration of the rollability due to deterioration ofmotion properties of the main chain skeleton.

Here, NMR is used as a principal measurement means for certifyingwhether the main chain of the copolymer has a cyclic structure.Specifically, if a peak derived from a cyclic structure existing in themain chain (for example, a peak appearing at 10 ppm to 24 ppm as for athree-membered ring to a five-membered ring) cannot be observed, it isindicated that the main chain of the copolymer consists exclusively ofan acyclic structure.

Note that in the present Specification, the “main chain” refers to along chain part connecting bonding terminals of each unit in thecopolymer, and may be either a straight chain or a branched chaindepending on a chain structure of the copolymer. Namely, the “mainchain” is exclusive of branched parts which are not bonded to adjacentunits in each unit constituting the copolymer.

The cis-1,4 bond content, the ratio among all of the aromatic vinylunits of at least one aromatic vinyl unit existing in the amorphousparts inclusive of the conjugated diene units, the glass-transitiontemperature, etc. may be adjusted by, e.g. appropriately controllingconditions during polymerization by using monomers, such as the inputamount of the monomers, the order of charging the monomers, the numberof times of charging the monomers, the polymerization catalyst, etc.

A polystyrene equivalent weight-average molecular weight (Mw) of themulti-component copolymer of this disclosure is preferably 10,000 to10,000,000, more preferably 100,000 to 9,000,000, particularlypreferably 150,000 to 8,000,000. By setting the Mw of themulti-component copolymer to 10,000 or more, it is possible tosufficiently ensure the mechanical strength as a material of a rubberarticle, and by setting the Mw to 10,000,000 or less, it is possible tomaintain high operability. In particular, from the same viewpoint, inthe multi-component copolymer of this disclosure, inclusive of the casewhere the conjugated diene units consist exclusively of 1,3-butadieneunits, the Mw is preferably 100,000 to 1,000,000.

Furthermore, in the multi-component copolymer of this disclosure, amolecular weight distribution (Mw/Mn) represented by the ratio of thepolystyrene equivalent weight-average molecular weight (Mw) to apolystyrene equivalent number-average molecular weight (Mn) is 10.0 orless, more preferably 9.0 or less, particularly preferably 8.0 or less.By setting the molecular weight distribution of the multicomponentcopolymer to 10.0 or less, it is possible to obtain sufficienthomogeneity in physical properties of the multicomponent copolymer.

The aforementioned polystyrene equivalent weight average molecularweight and molecular weight distribution may be obtained via gelpermeation chromatography (GPC) with polystyrene as a standardsubstance.

The multi-component copolymer of this disclosure may have either astructure in which the conjugated diene units, the non-conjugated olefinunits and the aromatic vinyl units are linked linearly (linearstructure) or a structure in which at least any one of the conjugateddiene units, the non-conjugated olefin units and the aromatic vinylunits are linked in a manner forming branched chains (branchedstructure). Note that in the case where the multi-component copolymer ofthis disclosure has a branched structure, the branched chains may beeither binary or multiple (namely, the branched chain may include atleast two of the conjugated diene units, the non-conjugated olefin unitsand the aromatic vinyl units). Therefore, among the multi-componentcopolymers of this disclosure, the multi-component copolymer with abranched structure having binary or multiple branched chains can beclearly distinguished from a conventional graft copolymer formed withrespectively one different type of units in a chain as a stem and inside chains.

(Method for Producing Multicomponent Copolymer)

Next, an example of the method for producing the multi-componentcopolymer of this disclosure will be described in detail below. Theexample of the method for producing the multi-component copolymer ofthis disclosure is on the assumption of using a conjugated dienecompound, a non-conjugated olefin compound and an aromatic vinylcompound as monomers. The method includes at least polymerizationprocess, and may further include, as necessary, coupling process,rinsing process, and other processes.

<Polymerization Process>

The polymerization process is a process of polymerizing at least theconjugated diene compound, the non-conjugated olefin compound and thearomatic vinyl compound as monomers. In this connection, thepolymerization process preferably includes an operation adding andpolymerizing only the non-conjugated olefin compound and/or the aromaticvinyl compound under the existence of a catalyst, without adding theconjugated diene compound, and an operation adding at least theconjugated diene compound to perform polymerization. Examples of amethod for adjusting the ratio among all of the aromatic vinyl units ofat least one aromatic vinyl unit existing in amorphous parts inclusiveof the conjugated diene units in the multi-component copolymer to lessthan 50% include a method appropriately reducing the input amount of thearomatic vinyl compound during the period that the non-conjugated olefincompound exists as a monomer under the existence of a catalyst, andappropriately increasing the input amount of the aromatic vinyl compoundduring the period that the non-conjugated olefin compound does not existas a monomer.

Note that in the case of using a polymerization catalyst compositiondescribed below, since the conjugated diene compound has higherreactivity than the non-conjugated olefin compound and the aromaticvinyl compound, polymerization of the non-conjugated olefin compoundand/or the aromatic vinyl compound under the existence of the conjugateddiene compound is likely to be difficult. Moreover, in view of theproperties of the catalyst, it is likely to be difficult as well tofirst polymerize the conjugated diene compound, and then performadditional polymerization of the non-conjugated olefin compound and/orthe aromatic vinyl compound.

An arbitrary method may be used as the polymerization process, which mayinclude: a solution polymerization; a suspension polymerization; aliquid phase bulk polymerization; an emulsion polymerization; a gasphase polymerization; and a solid phase polymerization. When a solventis used for the polymerization reaction, any solvent may be used as longas inactive in the polymerization reaction, and examples of such solventmay include toluene, cyclohexane and normal hexane.

In the polymerization process, the polymerization reaction maypreferably be performed in an inert gas atmosphere, and preferably innitrogen or argon atmosphere. The polymerization temperature of thepolymerization reaction is not particularly limited, but is preferablyin the range of, for example, −100° C. to 200° C., and may also beapproximately the room temperature. An increase in polymerizationtemperature may reduce the cis-1,4-selectivity in the polymerizationreaction. The polymerization reaction is preferably performed underpressure in the range of 0.1 MPa to 10.0 MPa so as to allow theconjugated diene compound to be sufficiently introduced into thepolymerization system. Further, the reaction time of the polymerizationreaction is not particularly limited, and is preferably in the range of,for example, 1 second to 10 days, which may be selected as appropriatedepending on conditions such as the type of the catalyst and thepolymerization temperature.

In the polymerization of the conjugated diene compound, a polymerizationinhibitor such as methanol, ethanol, and isopropanol may be used to stopthe polymerization.

In this connection, the polymerization of the aforementionednon-conjugated olefin compound, aromatic vinyl compound and conjugateddiene compound is preferably performed under the existence of a firstpolymerization catalyst composition, a second polymerization catalystcomposition, or a third polymerization catalyst composition described inbelow.

—First Polymerization Catalyst Composition—

An initial polymerization catalyst composition (hereinafter, alsoreferred to as a “first polymerization catalyst composition”) will bedescribed.

The first polymerization catalyst composition contains:

component (A): rare-earth element compounds represented by the followingformula (I):M-(AQ¹)(AQ²)(AQ³)  (I)

(In formula (I), M is selected from scandium, yttrium or lanthanoidelements; (AQ)¹, (AQ)² and (AQ)³ are the same or different functionalgroups, where A is nitrogen, oxygen or sulfur and has at least one M-Abond).

In this connection, specific examples of the lanthanoid element in thecomponent (A) include lanthanum, cerium, praseodymium, neodymium,promethium, samarium, europium, gadolinium, terbium, dysprosium,holmium, erbium, thulium, ytterbium, and lutetium, which may be usedsingly or in a combination of two or more. The component (A) is acomponent capable of improving the catalytic activity in the reactionsystem, which enables reduction of the reaction time and rise of thereaction temperature.

Moreover, from the viewpoint of improving the catalytic activity and thereaction controllability, the M is preferably gadolinium.

Note that these components (A) may be used singly or in a combination oftwo or more.

The compound represented by the aforementioned formula (I) has at leastone M-A bond. Having one or more M-A bonds is advantageous in terms ofallowing each binding to be chemically equivalent and making a structurestable, thereby facilitating handling and enabling manufacture of themulti-component copolymer efficiently at a low cost. Note that thecompound represented by the formula (I) may contain a bond other thanM-A, for example, a bond of a metal other than the M and a hetero atomsuch as O and S, etc.

In the formula (I), in the case where A is nitrogen, examples of thefunctional groups represented by AQ¹, AQ² and AQ³ (i.e., NQ¹, NQ² andNQ³) include amide groups.

Examples of the amide groups include: aliphatic amide groups such asdimethyl amide group, diethyl amide group and diisopropyl amide group;aryl amide groups such as phenyl amide group, 2,6-di-tert-butylphenylamide group, 2,6-diisopropylphenyl amide group, 2,6-dineopentylphenylamide group, 2-tert-butyl-6-isopropylphenyl amide group,2-tert-butyl-6-neopentylphenyl amide group,2-isopropyl-6-neopentylphenyl amide group and 2,4,6-tert-butylphenylamide group; and bistrialkylsilyl amide groups such as bistrimethylsilylamide group. In particular, from the viewpoint of the solubility to analiphatic hydrocarbon, bistrimethylsilyl amide group is preferable.

These functional groups may be used singly or in a combination of two ormore.

In the formula (I), in the case where A is oxygen, examples of thefunctional groups represented by AQ¹, AQ² and AQ³ (i.e., OQ¹, OQ² andOQ³) include alkoxy groups, acyloxy groups and alkoxycarboxyl groups.The alkoxy group is preferably methoxy group, ethoxy group, isopropoxygroup, etc. The acyloxy group is preferably acetoxy group, valeroylgroup, pivaloyl group, etc.

These functional groups may be used singly or in a combination of two ormore.

In the formula (I), in the case where A is sulfur, examples of thefunctional groups represented by AQ¹, AQ² and AQ³ (i.e., SQ¹, SQ² andSQ³) include alkylthio groups and alkylsulfonyl groups. The alkylthiogroup is preferably methylthio group, isopropylthio group, etc. Thealkylsulfonyl group is preferably phenylsulfonyl group,isopropanesulfonyl group, hexanesulfonyl group, etc.

These functional groups may be used singly or in a combination of two ormore.

Note that in the polymerization reaction system, it is preferable that aconcentration of the component (A) contained in the catalyst compositionis in the range of 0.1 mol/L to 0.0001 mol/L.

The first polymerization catalyst composition preferably furthercontains:

component (B): at least one selected from a group consisting of aspecific ionic compound (B-1) and a specific halogen compound (B-2)

component (C): a compound represented by the following formula (II):YR¹ _(a)R² _(b)R³ _(c)  (II)

(In formula (II), Y is a metal selected from groups 1, 2, 12 and 13 inthe periodic table; R¹ and R² are hydrocarbon groups having a carbonnumber of 1 to 10 or hydrogen atoms and R³ is a hydrocarbon group havinga carbon number of 1 to 10 where R′, R² and R³ are the same ordifferent, and a=1, b=0, and c=0 in the case where Y is a metal selectedfrom the group 1 in the periodic table, a=1, b=1, and c=0 in the casewhere Y is a metal selected from the groups 2 and 12 in the periodictable, and a=1, b=1, and c=1 in the case where Y is a metal selectedfrom the group 13 in the periodic table).

If the first polymerization catalyst composition further contains thecomponents (B) and (C), it is possible to produce the multi-componentcopolymer of the conjugated diene compound, the non-conjugated olefincompound and the aromatic vinyl compound more efficiently.

The ionic compound (B-1) and the halogen compound (B-2) need thecomponent (C) serving as a carbon donor to the component (A) becauseneither the ionic compound (B-1) nor the halogen compound (B-2) has acarbon atom which can be supplied to the component (A). The firstpolymerization catalyst composition may further include other componentsincluded in a conventional metallocene complex-containing polymercatalyst composition, e.g., a co-catalyst.

The total content of the component (B) in the first polymerizationcatalyst composition is preferably 0.1 to 50 times as much as thecontent of the component (A) in the composition when compared in mol.

The ionic compound as the (B-1) is an ionic compound constituted of anon-coordinating anion and a cation. Examples of the ionic compound(B-1) include an ionic compound capable of being reacted with the rareearth element compound as the compound (A), to generate a cationictransition metal compound.

In this connection, examples of the non-coordinating anion includetetraphenyl borate, tetrakis(monofluorophenyl)borate,tetrakis(difluorophenyl)borate, tetrakis(trifluorophenyl)borate,tetrakis(tetrafluorophenyl)borate, tetrakis(pentafluorophenyl)borate,tetrakis(tetrafluoromethylphenyl)borate, tetra(tolyl)borate,tetra(xylyl)borate, triphenyl(pentafluorophenyl)borate,[tris(pentafluorophenyl)](phenyl)borate,tridecahydride-7,8-dicarbaundecaborate, and the like. Examples of thecation include carbonium cation, oxonium cation, ammonium cation,phosphonium cation, cycloheptatrienyl cation, ferrocenium cation havingtransition metal, and the like. Specific examples of carbonium ioninclude trisubstituted carbonium cation such as triphenylcarboniumcation, tri(substituted phenyl)carbonium cation, and the like. Specificexamples of the tri(substituted phenyl)carbonium cation includetri(methylphenyl)carbonium cation, tri(dimethylphenyl)carbonium cation,and the like. Specific examples of the ammonium cation include:trialkylammonium cation such as trimethylammonium cation,triethylammonium cation, tripropylammonium cation, tributylammoniumcation (e.g., tri(n-butyl)ammonium cation); N,N-dialkylanilinium cationsuch as N,N-dimethylanilinium cation, N,N-diethylanilinium cation,N,N-2,4,6-pentamethylanilinium cation, and the like; and dialkylammoniumcation such as diisopropylammonium cation, dicyclohexylammonium cation,and the like. Specific examples of phosphonium cation includetriarylphosphonium cation such as triphenylphosphonium cation,tri(methylphenyl)phosphonium cation, tri(dimethylphenyl)phosphoniumcation, and the like. A compound as a combination of a non-coordinatinganion and a cation selected from the aforementioned examples,respectively, is preferably used as the ionic compound. Specificexamples of the ionic compound include N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, triphenylcarboniumtetrakis(pentafluorophenyl)borate, and the like. These ionic compoundsmay be used singly or in a combination of two or more.

The total content of the ionic compound (B-1) in the catalystcomposition is preferably 0.1 to 10 times, more preferably 1 time asmuch as the content of the component (A) in the composition whencompared in mol.

The halogen compound as the (B-2) is at least one type of halogencompound selected from a Lewis acid, a complex compound of a metalhalide and a Lewis base, or an organic compound containing an activehalogen. The halogen compound (B-2) is capable of being reacted with therare earth element compound as the component (A), to generate a cationictransition metal compound, a halide transition metal compound, or acompound with a charge-deficient transition metal center.

The total content of the halogen compound (B-2) in the firstpolymerization catalyst composition is preferably 1 to 5 times as muchas the content of the component (A) when compared in mol.

Examples of the Lewis acid which can be used in this disclosure includea boron-containing halogen compound such as B(C₆F₅)₃, analuminum-containing halogen compound such as Al(C₆F₅)₃, and a halogencompound containing a group 3, 4, 5, 6 or 8 element in the periodictable. Preferable examples of the Lewis acid include aluminum halide andorganic metal halide. Chlorine or bromine is preferable as the halogenelement. Specific examples of the Lewis acid include methyl aluminumdibromide, methyl aluminum dichloride, ethyl aluminum dibromide, ethylaluminum dichloride, butyl aluminum dibromide, butyl aluminumdichloride, dimethyl aluminum bromide, dimethyl aluminum chloride,diethyl aluminum bromide, diethyl aluminum chloride, dibutyl aluminumbromide, dibutyl aluminum chloride, methyl aluminum sesquibromide,methyl aluminum sesquichloride, ethyl aluminum sesquibromide, ethylaluminum sesquichloride, dibutyl tin dichloride, aluminum tribromide,antimony trichloride, antimony pentachloride, phosphorus trichloride,phosphorus pentachloride, tin tetrachloride, titanium tetrachloride,tungsten hexachloride, and the like. Diethyl aluminum chloride, ethylaluminum sesquichloride, ethyl aluminum dichloride, diethyl aluminumbromide, ethyl aluminum sesquibromide, and ethyl aluminum dibromide areparticularly preferable as the Lewis acid among these examples.

Examples of the metal halide which, together with a Lewis base,constitutes a complex compound include beryllium chloride, berylliumbromide, beryllium iodide, magnesium chloride, magnesium bromide,magnesium iodide, calcium chloride, calcium bromide, calcium iodide,barium chloride, barium bromide, barium iodide, zinc chloride, zincbromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide,mercury chloride, mercury bromide, mercury iodide, manganese chloride,manganese bromide, manganese iodide, rhenium chloride, rhenium bromide,rhenium iodide, copper chloride, copper bromide, copper iodide, silverchloride, silver bromide, silver iodide, gold chloride, gold iodide,gold bromide, and the like. Magnesium chloride, calcium chloride, bariumchloride, manganese chloride, zinc chloride, copper chloride arepreferable as the metal halide among these examples. Magnesium chloride,manganese chloride, zinc chloride, copper chloride are particularlypreferable.

Further, preferable examples of the Lewis base constituting, togetherwith the metal halide, a complex compound include a phosphorus compound,a carbonyl compound, a nitrogen compound, an ether compound, alcohol,and the like. Specifically, acceptable examples of the Lewis baseinclude tributyl phosphate, tris(2-ethylhexyl) phosphate, triphenylphosphate, tricresyl phosphate, triethylphosphine, tributylphosphine,triphenylphosphine, diethylphosphinoethane, diphenylphosphinoethane,acetylacetone, benzoylacetone, propionitrileacetone, valerylacetone,ethylacetylacetone, methyl acetoacetate, ethyl acetoacetate, phenylacetoacetate, dimethyl malonate, diethyl malonate, diphenyl malonate,acetic acid, octanoic acid, 2-ethyl-hexanoic acid, oleic acid, stearicacid, benzoic acid, naphthenic acid, versatic acid, triethylamine,N,N-dimethylacetamide, tetrahydrofuran, diphenyl ether, 2-ethyl-hexylalcohol, oleyl alcohol, stearyl alcohol, phenol, benzyl alcohol,1-decanol, lauryl alcohol, and the like. Tris(2-ethylhexyl) phosphate,tricresyl phosphate, acetylacetone, 2-ethyl-hexanoic acid, versaticacid, 2-ethyl-hexyl alcohol, 1-decanol, lauryl alcohol are preferable asthe Lewis base among these examples.

0.01 to 30 mol (preferably 0.5 to 10 mol) per 1 mol of the metal halide,of the aforementioned Lewis base, is reacted with the metal halide.Metals remaining in the copolymer can be reduced by using a reactantobtained by this reaction between the metal halide and the Lewis base.

Examples of the organic compound containing active halogen includebenzyl chloride and the like.

These halogen compounds may be used singly or in a combination of two ormore.

The component (C) for use in the first polymerization catalystcomposition is a compound represented by the following formula (II):YR¹ _(a)R² _(b)R³ _(c)  (II)

(In formula (II), Y is a metal selected from groups 1, 2, 12 and 13 inthe periodic table; R¹ and R² are hydrocarbon groups with a carbonnumber of 1 to 10 or hydrogen atoms and R³ is a hydrocarbon group with acarbon number of 1 to 10 where R¹, R² and R³ are the same or different,and a=1, b=0, and c=0 in the case where Y is a metal selected from thegroup 1 in the periodic table, a=1, b=1, and c=0 in the case where Y isthe metal selected from the groups 2 and 12 in the periodic table, anda=1, b=1, and c=1 in the case where Y is the metal selected from thegroup 13 in the periodic table), preferably an organic aluminum compoundrepresented by the following formula (III):AlR¹R²R³  (III)

(In formula (III), R¹ and R² are hydrocarbon groups with a carbon numberof 1 to 10 or hydrogen atoms and R³ is a hydrocarbon group with a carbonnumber of 1 to 10 where R¹, R² and R³ are the same or different).Examples of the organic aluminum compound represented by general formula(III) include trimethyl aluminum, triethyl aluminum, tri-n-propylaluminum, triisopropyl aluminum, tri-n-butyl aluminum, triisobutylaluminum, tri-t-butyl aluminum, tripentyl aluminum, trihexyl aluminum,tricyclohexyl aluminum, trioctyl aluminum; diethyl aluminum hydride,di-n-propyl aluminum hydride, di-n-butyl aluminum hydride, diisobutylaluminum hydride, dihexyl aluminum hydride, diisohexyl aluminum hydride,dioctyl aluminum hydride, diisooctyl aluminum hydride, ethyl aluminumdihydride, n-propyl aluminum dihydride, isobutyl aluminum dihydride, andthe like. Triethyl aluminum, triisobutyl aluminum, diethyl aluminumhydride and diisobutyl aluminum hydride are preferable as the organicaluminum compound among these examples. The organic aluminum compoundsas the component (C) described above may be used singly or in acombination of two or more. The content of the organic aluminum compoundin the first polymerization catalyst composition is preferably 1 to 50times, more preferably approximately 10 times, as much as the content ofthe component (A) when compared in mol.

From the viewpoint of synthesizing a copolymer with a high cis-1,4 bondcontent at a high yield, it is more preferable that the firstpolymerization catalyst composition further contains:

component (D): a coordination compound capable of serving as an anionicligand.

The component (D) is not specifically limited as long as exchangeablefor the functional groups represented by AQ¹, AQ² and AQ³ of thecomponent (A). Examples of the component (D) include one having any oneof OH group, NH group and SH group.

Specific examples of the component (D) as a compound having OH groupinclude aliphatic alcohol, aromatic alcohol, and the like. Specificexamples of aliphatic alcohol and aromatic alcohol include, but are notlimited to, 2-ethyl-1-hexanol, dibutylhydroxytoluene, alkylated phenol,4,4′-thiobis-(6-t-butyl-3-methylphenol),4,4′-butylidenebis-(6-t-butyl-3-methylphenol),2,2′-methylenebis-(4-methyl-6-t-butylphenol),2,2′-methylenebis-(4-ethyl-6-t-butylphenol), 2,6-di-t-4-ethylphenol,1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane,n-octadecyl-3-(4-hydroxy-3,5,-di-t-butylphenyl)propionate,tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane,dilaurylthiodipropionate, distearylthiodipropionate, dimyristylylthiopropionate, and the like. Examples of hindered-phenol basedcompounds in this connection include triethyleneglycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate],1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-4-hydroxyphenyl)propionate],2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine,pentaerythryl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],2,2-thiodiethylene-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,N,N′-hexamethylene-bis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide),3,5-t-butyl-4-hydroxybenzylphosphonate-diethyl ester,1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, octylateddiphenylamine, 2,4-bis[(octylthio)methyl]⁻o-cresol, and the like.Further, examples of hydrazine based compounds in this connectioninclude N,N′-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine.

Specific examples of the component (D) having NH group include primaryamines and secondary amines such as alkylamine, arylamine and the like.Specific examples of the primary and secondary amines includedimethylamine, diethylamine, pyrrole, ethanolamine, diethanolamine,dicyclohexylamine, N,N′-dibenzylethylenediamine,bis(2-diphenylphosphinophenyl)amine, and the like.

Specific examples of the component (D) having SH group include aliphaticthiol, aromatic thiol, and compounds represented by the followingformulae (VI) and (VII).

(In formula (VI), R¹, R² and R³ each independently represent—O—C_(j)H_(2j+1), —(O—C_(k)H_(2k)—)_(a)—O—C_(m)H_(2m+1), or—C_(n)H_(2n+1); at least one of R¹, R² and R³ is—(O—C_(k)H_(2k)—)_(a)—O—C_(m)H_(2m+1); j, m and n each independentlyrepresent an integer in the range of 0 to 12; k and a each independentlyrepresent an integer in the range of 1 to 12; and R₄ represents anormal/branched/cyclic, saturated/unsaturated alkylene group,cycloalkylene group, cycloalkylalkylene group, cycloalkenyl alkylenegroup, alkenylene group, cycloalkenylene group, cycloalkyl alkenylenegroup, cycloalkenyl alkenylene group, arylene group, or aralkylenegroup, with a carbon number of an integer in the range of 1 to 12.)

Specific examples of the compounds represented by formula (VI) include(3-mercaptopropyl)trimethoxysilane, (3-mercaptopropyl)triethoxysilane,(3-mercaptopropyl)methyldimethoxysilane,(mercaptomethyl)dimethylethoxysilane, (mercaptomethyl)trimethoxysilane,and the like.

(In formula (VII), W represents —NR⁸—, —O—, or —CR⁹R¹⁰— (R⁸ and R⁹ eachrepresent —C_(p)H_(2p+1), R¹⁰ represents —C_(q)H_(2q+1), and p and qeach independently represent an integer in the range of 0 to 20); R⁵ andR⁶ each independently represent -M-C_(r)H_(2r)— (M represents —O— or—CH₂—, r represents an integer in the range of 1 to 20); R⁷ represents—O—C₁H_(2j+1), —(O—C_(k)H_(2k)—)_(a)—O—C_(m)H_(2m+1), or —C_(n)H_(2n+1);j, m and n each independently represent an integer in the range of 0 to12; k and a each independently represent an integer in the range of 1 to12; and R⁴ represents a normal/branched/cyclic, saturated/unsaturatedalkylene group, cycloalkylene group, cycloalkylalkylene group,cycloalkenylalkylene group, alkenylene group, cycloalkenylene group,cycloalkylalkenylene group, cycloalkenylalkenylene group, arylene group,or aralkylene group, with a carbon number of 1 to 12.)

Specific examples of the compounds represented by formula (VII) include3-mercaptopropyl(ethoxy)-1,3-dioxa-6-methylaza-2-silacyclooctane,3-mercaptopropyl(ethoxy)-1,3-dioxa-6-butylaza-2-silacyclooctane,3-mercaptopropyl(ethoxy)-1,3-dioxa-6-dodecylaza-2-silacyclooctane, andthe like.

It is preferable that the coordination compound as the component (D) isa compound having a cyclopentadiene skeleton.

Further, the compound having a cyclopentadiene skeleton is notspecifically limited as long as having a cyclopentadiene skeleton, butis more preferably a compound having indenyl group from the viewpoint ofobtaining higher catalytic activity. This is because that it is possibleto enhance the activity without using toluene, which has greaterenvironmental load as a solvent used in polymerization.

In this connection, examples of the compound having indenyl groupinclude indene, 1-methylindene, 1-ethylindene, 1-benzylindene,2-phenylindene, 2-methylindene, 2-ethylindene, 2-benzylindene,3-methylindene, 3-ethylindene and 3-benzylindene, among which asubstituted phenylindenyl compound is preferable.

The component (D) is added by preferably 0.01 to 10 mol, more preferably0.1 to 1.2 mol, per 1 mol of the rare earth element compound as thecomponent (A). When the component (D) is added by less than 0.01 mol per1 mol of the rare earth element compound, polymerization of the monomersmay not proceed in a satisfactory manner. Adding the component (D) by anamount chemically equivalent to the rare earth element compound (1.0mol) is particularly preferable and the amount may exceed 1.0 mol.Adding the component (D) by an amount exceeding 10 mol per 1 mol of therare earth element compound, however, is not recommendable because thentoo much reagents will be wasted.

—Second Polymerization Catalyst Composition—

Next, a secondary polymerization catalyst composition (hereinafter, alsoreferred to as a “second polymerization catalyst composition”) will bedescribed. The second polymerization catalyst composition is apolymerization catalyst composition containing at least one type ofcomplex selected from the group consisting of:

a metallocene complex represented by following formula (IX)

(In formula (IX), M represents a lanthanoid element, scandium oryttrium; Cp^(R)s each independently represent unsubstituted/substitutedindenyl; R^(a) to R^(f) each independently represent an alkyl group witha carbon number of 1 to 3 or hydrogen atom; L represents a neutral Lewisbase; and w represents an integer in the range of 0 to 3);

a metallocene complex represented by following formula (X)

(In formula (X), M represents a lanthanoid element, scandium or yttrium;Cp^(R)s each independently represent unsubstituted/substituted indenyl;X′ represents hydrogen atom, halogen atom, alkoxide group, thiolategroup, amide group, silyl group, or a hydrocarbon group having a carbonnumber of 1 to 20; L represents a neutral Lewis base; and w representsan integer in the range of 0 to 3); and

a half metallocene cation complex represented by following formula (XI)

(In formula (XI), M represents a lanthanoid element, scandium oryttrium; Cp^(R′) represents unsubstituted/substituted cyclopentadienyl,indenyl or fluorenyl; X represents hydrogen atom, halogen atom, alkoxidegroup, thiolate group, amide group, silyl group, or a hydrocarbon grouphaving a carbon number of 1 to 20; L represents a neutral Lewis base;and w represents an integer in the range of 0 to 3); and [B]⁻ representsa non-coordinating anion).

The second polymerization catalyst composition may further include othercomponents included in a conventional metallocene complex-containingpolymer catalyst composition, e.g., a co-catalyst. In this disclosure, a“metallocene complex” represents a complex compound in which at leastone cyclopentadienyl or derivative thereof is bonded to a core metal. Inthis connection, a metallocene complex in which only a singlecyclopentadienyl or derivative thereof is bonded to a core metal mayoccasionally be referred to as a “half metallocene complex” inparticular.

The concentration of the complex contained in the second polymerizationcatalyst composition is preferably in the range of 0.1 mol/L to 0.0001mol/L in the polymerization reaction system.

Cp^(R)s are unsubstituted/substituted indenyls in the metallocenecomplexes represented by formula (IX) and formula (X). Cp^(R) having anindenyl ring as the base skeleton may be represented as C₉H_(7-X)R_(X)or C₉H_(11-X)R_(X), wherein X is an integer in the range of 0 to 7 or 0to 11; Rs preferably each represent hydrocarbyl group or metalloidgroup; and the carbon number of the hydrocarbyl group is preferably inthe range of 1 to 20, more preferably in the range of 1 to 10, and evenmore preferably in the range of 1 to 8. Specifically, preferableexamples of the hydrocarbyl group include methyl group, ethyl group,phenyl group, benzyl group and the like. Examples of metalloid of themetalloid group include germyl Ge, stannyl Sn, and silyl Si. Themetalloid group preferably includes a hydrocarbyl group which is definedin the same manner as the aforementioned hydrocarbyl group. Specificexamples of the metalloid group include trimethylsilyl and the like.Specific examples of the substituted indenyl include 2-phenylindenyl,2-methylindenyl, and the like. Cp^(R)s in formula (IX) and formula (X)may be of either the same type or different types.

Cp^(R′) is unsubstituted/substituted cyclopentadienyl, indenyl, orfluorenyl group in the half metallocene cation complex represented byformula (XI). Unsubstituted/substituted indenyl group is preferable asCp^(R′) among these examples. Cp^(R′) having a cyclopentadienyl ring asthe base skeleton is represented as C₅H_(5-X)R_(X), wherein X is aninteger in the range of 0 to 5; Rs preferably each independentlyrepresent hydrocarbyl group or metalloid group; and the carbon number ofthe hydrocarbyl group is preferably in the range of 1 to 20, morepreferably in the range of 1 to 10, and even more preferably in therange of 1 to 8. Specifically, preferable examples of the hydrocarbylgroup include methyl group, ethyl group, phenyl group, benzyl group andthe like. Examples of metalloid of the metalloid group include germylGe, stannyl Sn, and silyl Si. The metalloid group preferably includes ahydrocarbyl group which is defined in the same manner as theaforementioned hydrocarbyl group. Specific examples of the metalloidgroup include trimethylsilyl and the like. Specific examples of Cp^(R′)having a cyclopentadienyl ring as the base skeleton include compoundsrepresented by the following structural formulae:

(In these structural formulae, R represents hydrogen atom, methyl groupor ethyl group.)

Cp^(R′) having an indenyl ring as the base skeleton, as well aspreferable examples thereof, in formula (XI) is defined in the samemanner as Cp^(R) in formula (IX).

Cp^(R′) having a fluorenyl ring as the base skeleton in formula (XI) isrepresented as C₁₃H_(9-X)R_(X) or C₁₃H_(17-X)R_(X), wherein X is aninteger in the range of 0 to 9 or 0 to 17; Rs preferably eachindependently represent hydrocarbyl group or metalloid group; and thecarbon number of the hydrocarbyl group is preferably in the range of 1to 20, more preferably in the range of 1 to 10, and even more preferablyin the range of 1 to 8. Specifically, preferable examples of thehydrocarbyl group include methyl group, ethyl group, phenyl group,benzyl group and the like. Examples of metalloid of the metalloid groupinclude germyl Ge, stannyl Sn, and silyl Si. The metalloid grouppreferably includes a hydrocarbyl group which is defined in the samemanner as the aforementioned hydrocarbyl group. Specific examples of themetalloid group include trimethylsilyl and the like.

The core metal M in each of formulae (IX), (X) and (XI) is a lanthanoidelement, scandium or yttrium. The lanthanoid elements include elementshaving atomic numbers 57 to 71 in the periodic table and any of theseelements is acceptable. Preferable examples of the core metal M includesamarium Sm, neodymium Nd, praseodymium Pr, gadolinium Gd, cerium Ce,holmium Ho, scandium Sc, and yttrium Y.

The metallocene complex represented by formula (IX) includes a silylamide ligand [—N(SiR₃)₂]. R groups included in the silyl amide ligand(i.e. R^(a) to R^(f) in formula (IX)) each independently represent analkyl group having a carbon number of 1 to 3 or a hydrogen atom. It ispreferable that at least one of R^(a) to R^(f) is a hydrogen atom. Thecatalyst can be easily synthesized and a non-conjugated olefin or anaromatic vinyl compound is easily introduced due to relatively littlehindrance around the silicon atom when at least one of R^(a) to R^(f) isa hydrogen atom. For similar reasons, it is more preferable that atleast one of R^(a) to R^(c) is a hydrogen atom and at least one of R^(d)to R^(f) is a hydrogen atom. Methyl group is preferable as the alkylgroup.

The metallocene complex represented by formula (X) includes a silylligand [—SiX′₃]. X′ groups included in the silyl ligand [—SiX′₃], aswell as preferable examples thereof, are defined in the same manner as Xgroup in formula (XI) described below.

In formula (XI), X is a group selected from the group consisting ofhydrogen atom, halogen atom, alkoxide group, thiolate group, amidegroup, silyl group, and a hydrocarbon group having a carbon number of 1to 20. Examples of the alkoxide group include: aliphatic alkoxy groupsuch as methoxy group, ethoxy group, propoxy group, n-butoxy group,isobutoxy group, sec-butoxy group, tert-butoxy group, and the like; andaryloxide group such as phenoxy group, 2,6-di-tert-butylphenoxy group,2,6-diisopropylphenoxy group, 2,6-dineopentylphenoxy group,2-tert-butyl-6-isopropylphenoxy group, 2-tert-butyl-6-neopentylphenoxygroup, 2-isopropyl-6-neopentylphenoxy group, and the like.2,6-di-tert-butylphenoxy group is preferable as the alkoxide group amongthese examples.

Examples of the thiolate group represented by X in formula (XI) include:aliphatic thiolate group such as thiomethoxy group, thioethoxy group,thiopropoxy group, n-thiobutoxy group, thoisobutoxy group,sec-thiobutoxy group, tert-thiobutoxy group, and the like; andarylthiolate group such as thiophenoxy group,2,6-di-tert-butylthiophenoxy group, 2,6-diisopropylthiophenoxy group,2,6-dineopentylthiophenoxy group, 2-tert-butyl-6-isopropylthiophenoxygroup, 2-tert-butyl-6-thioneopentylphenoxy group,2-isopropyl-6-thioneopentylphenoxy group, 2,4,6-triisopropylthiophenoxygroup, and the like. 2,4,6-triisopropylthiophenoxy group is preferableas the thiolate group among these examples.

Examples of the amide group represented by X in formula (XI) include:aliphatic amide group such as dimethyl amide group, diethyl amide group,diisopropyl amide group, and the like; aryl amide group such as phenylamide group, 2,6-di-tert-butylphenyl amide group, 2,6-diisopropylphenylamide group, 2,6-dineopentylphenyl amide group,2-tert-butyl-6-isopropylphenyl amide group,2-tert-butyl-6-neopentylphenyl amide group,2-isopropyl-6-neopentylphenyl amide group, 2,4,6-tri-tert-butylphenylamide group, and the like; and bistrialkylsilyl amide group such asbistrimethylsilyl amide group and the like. Bistrimethylsilyl amidegroup is preferable as the amide group among these examples.

Examples of the silyl group represented by X in formula (XI) includetrimethylsilyl group, tris(trimethylsilyl)silyl group,bis(trimethylsilyl)methylsilyl group, trimethylsilyl(dimethyl)silylgroup, (triisopropylsilyl)bis(trimethylsilyl)silyl group, and the like.Tris(trimethylsilyl)silyl group is preferable as the silyl group amongthese examples.

Acceptable examples of the halogen atom represented by X in formula (XI)include fluorine, chlorine, bromine and iodine atoms. Chlorine orbromine atom is preferable. Specific examples of the hydrocarbon grouphaving a carbon number of 1 to 20 represented by X in formula (XI)include: normal/branched aliphatic hydrocarbon group such as methylgroup, ethyl group, n-propyl group, isopropyl group, n-butyl group,isobutyl group, sec-butyl group, tert-butyl group, neopentyl group,hexyl group, octyl group; aromatic hydrocarbon group such as phenylgroup, tolyl group, naphthyl group; aralykyl group such as benzyl group;a hydrocarbon group containing silicon atom such as trimethylsilylmethylgroup, bistrimethylsilylmethyl group; and the like. Methyl group, ethylgroup, isobutyl group, trimethylsilylmethyl group, and the like arepreferable as the hydrocarbon group having a carbon number of 1 to 20among these examples.

Bistrimethylsilyl amide group or a hydrocarbon group having a carbonnumber of 1 to 20 is preferable as X in formula (XI).

Examples of the non-coordinating anion represented by [B]⁻ in formula(XI) include quadrivalent boron anion. Specific examples of thequadrivalent boron anion include tetraphenyl borate,tetrakis(monofluorophenyl)borate, tetrakis(difluorophenyl)borate,tetrakis(trifluorophenyl)borate, tetrakis(tetrafluorophenyl)borate,tetrakis(pentafluorophenyl)borate,tetrakis(tetrafluoromethylphenyl)borate, tetra(tolyl)borate,tetra(xylyl)borate, triphenyl(pentafluorophenyl)borate,[tris(pentafluorophenyl)phenyl]borate,tridecahydride-7,8-dicarbaundecaborate, and the like.

Tetrakis(pentafluorophenyl)borate is preferable as the quadrivalentboron anion among these examples.

The metallocene complexes represented by formulae (IX) and (X) and thehalf metallocene cation complex represented by general formula (XI) eachfurther include 0 to 3, preferably 0 to 1, neutral Lewis base L.Examples of the neutral Lewis base L include tetrahydrofuran, diethylether, dimethylaniline, trimethylphosphine, lithium chloride, neutralolefin, neutral diolefin, and the like. The neutral Lewis bases L may beof either the same type or different types when the complex includes aplurality of neutral Lewis bases L.

The metallocene complexes represented by formulae (IX) and (X) and thehalf metallocene cation complex represented by general formula (XI) mayeach exist as any of monomer, dimer or another type of multimer.

The metallocene complex represented by formula (IX) can be obtained by,for example, reacting lanthanoid trishalide, scandium trishalide oryttrium trishalide with an indenyl salt (such as potassium or lithiumindenyl salt) and a bis(trialkylsilyl)amide salt (such as potassium orlithium salt of bis(trialkylsilyl)amide) in a solvent. The reactiontemperature may be set around the room temperature, which allowsproduction in a mild condition. The reaction time may be set as desiredand is generally in the range of a few hours to a few days. Type of thereaction solvent is not particularly limited but preferably a solventcapable of dissolving the raw materials and a reaction product. Forexample, toluene can be used. An example of a reaction for obtaining themetallocene complex represented by formula (IX) is presented below.

(In the reaction example above, X″ represents a halide.)

The metallocene complex represented by formula (X) can be obtained by,for example, reacting lanthanoid trishalide, scandium trishalide oryttrium trishalide with an indenyl salt (such as potassium or lithiumindenyl salt) and a silyl salt (such as potassium or lithium silyl salt)in a solvent. The reaction temperature may be set around the roomtemperature, which allows production in a mild condition. The reactiontime may be set as desired and is generally in the range of a few toseveral tens of hours. Type of the reaction solvent is not particularlylimited but preferably a solvent capable of dissolving the raw materialsand a reaction product. For example, toluene can be used. An example ofa reaction for obtaining the metallecene complex represented by formula(X) is presented below.

(In the reaction example above, X″ represents a halide.)

The half metallocene cation complex represented by formula (XI) can beobtained, for example, by a reaction presented below.

In the compound represented by formula (XII), M represents a lanthanoidelement, scandium or yttrium; Cp^(R′)s each independently representunsubstituted/substituted cyclopentadienyl, indenyl or fluorenyl; and Xrepresents hydrogen atom, halogen atom, alkoxide group, thiolate group,amide group, silyl group, or a hydrocarbon group having a carbon numberof 1 to 20. L represents a neutral Lewis base and w represents aninteger in the range of 0 to 3. [A]⁺ represents a cation and [B]⁻represents a non-coordinating anion in an ionic compound represented by[A]⁺[B]⁻.

Examples of the cation represented by [A]⁺ include carbonium cation,oxonium cation, amine cation, phosphonium cation, cycloheptatrienylcation, ferrocenium cation having transition metal, and the like.Examples of the carbonium cation include trisubstituted carbonium cationsuch as triphenylcarbonium cation, tri(substituted phenyl)carboniumcation, and the like. Specific examples of the tri(substitutedphenyl)carbonium cation include tri(methylphenyl)carbonium cation.Examples of the amine cation include: trialkylammonium cation such astrimethylammonium cation, triethylammonium cation, tripropylammoniumcation, tributylammonium cation; N,N-dialkylanilinium cation such asN,N-dimethylanilinium cation, N,N-diethylanilinium cation,N,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cation suchas diisopropylammonium cation, dicyclohexylammonium cation, and thelike. Examples of phosphonium cation include triarylphosphonium cationsuch as triphenylphosphonium cation, tri(methylphenyl)phosphoniumcation, tri(dimethylphenyl)phosphonium cation, and the like.N,N-dialkylanilinium cation or carbonium cation is preferable andN,N-dialkylanilinium cation is particularly preferable as [A]⁺ amongthese examples.

The ionic compound represented by general formula [A]⁺[B]⁻ for use inthe aforementioned reaction is, for example, a compound obtained bycombining a non-coordinating anion and a cation respectively selectedfrom the aforementioned examples and preferably N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, triphenylcarboniumtetrakis(pentafluorophenyl)borate, and the like. The ionic compoundrepresented by general formula [A]⁺[B]⁻ is added to the metallocenecomplex by an amount preferably 0.1 to 10 times, more preferablyapproximately 1 time, as much as the amount of the metallocene complex.In the case where the half metallocene cation complex represented byformula (XI) is used for a polymerization reaction, the half metallocenecation complex represented by formula (XI) may be directly provided intoa polymerization reaction system or, alternatively, the half metallocenecation complex represented by formula (XI) may be formed in apolymerization reaction system by providing a compound represented byformula (XII) and the ionic compound represented by general formula[A]⁺[B]⁻ for use in the aforementioned reaction, respectively, in thepolymerization reaction system. Further alternatively, the halfmetallocene cation complex represented by formula (XI) may be formed ina polymerization reaction system by using the metallocene complexrepresented by formula (IX) or formula (X) and the ionic compoundrepresented by formula [A]⁺[B]⁻ for use in the aforementioned reactionin a combined manner in the polymerization reaction system.

Structures of the metallocene complex represented by formula (IX) orformula (X) and the half metallocene cation complex represented byformula (XI) are each preferably obtained through x-ray structuralanalysis.

The co-catalyst applicable to the second polymerization catalystcomposition can be selected according to necessity from components usedas co-catalysts in a conventional polymerization catalyst compositioncontaining a metallocene complex. Preferable examples of the co-catalystinclude aluminoxane, an organic aluminum compound, the ionic compoundsdescribed above, and the like. These co-catalysts may be used singly orin a combination of two or more.

The aforementioned aluminoxane is preferably alkylaluminoxane andexamples thereof include methyl aluminoxane (MAO), modified methylaluminoxane, and the like. “MMAO-3A”, manufactured by Tosoh FinechemCorporation, or the like is preferable as the modified methylaluminoxane. Provided that “Al/M” represents an element ratio of thealuminum element Al of the aluminoxane with respect to the core metal Mof the metallocene complex, the content of the aluminoxane in the secondpolymerization catalyst composition is set such that the element ratioAl/M is in the range of 10 to 1000 approximately, preferably around 100.

On the other hand, the aforementioned organic aluminum compound ispreferably an organic aluminum compound represented by general formulaAlRR′R″ (in the formula, R and R′ each independently represent ahydrocarbon group having a carbon number of 1 to 10 or a hydrogen atomand R″ represents a hydrocarbon group having a carbon number of 1 to10). Examples of the organic aluminum compound include trialkylaluminum, dialkyl aluminum chloride, alkyl aluminum dichloride, dialkylaluminum hydride, and the like. Trialkyl aluminum is preferable as theorganic aluminum compound among these examples. Examples of trialkylaluminum include triethyl aluminum, triisobutyl aluminum, and the like.The content of the organic aluminum compound in the aforementionedpolymerization catalyst composition is preferably 1 to 50 times, morepreferably around 10 times, as much as the content of the metallocenecomplex in the composition when compared in mol.

The cis-1,4 bond content and/or the molecular weight of a resultingpolymer can be increased by using each of the metallocene complexrepresented by formula (IX) or formula (X) and the half metallocenecation complex represented by formula (XI) with an appropriateco-catalyst in combination in the second polymerization catalystcomposition.

—Third Polymerization Catalyst Composition—

Next, a tertiary polymerization catalyst composition (hereinafter, alsoreferred to as a “third polymerization catalyst composition”) will bedescribed.

The third polymerization catalyst composition is a compound containing arare earth element and examples thereof include a polymerizationcatalyst composition containing a metallocene-based composite catalystrepresented by the following formula (XIII)R_(a)MX_(b)QY_(b)  (XIII)

(In formula (XIII), Rs each independently representunsubstituted/substituted indenyl; M is coordinated with Rs; Mrepresents a lanthanoid element, scandium or yttrium; Xs eachindependently represent a hydrocarbon group having a carbon number of 1to 20; M and Q are μ-coordinated with X; Q represents a group 13 elementin the periodic table; Ys each independently represent a hydrocarbongroup having a carbon number of 1 to 20 or a hydrogen atom; Q iscoordinated with Y; and a=b=2).

Preferable examples of the aforementioned metallocene-based compositecatalyst include a metallocene-based composite catalyst represented bythe following formula (XIV):

(In formula (XIV), M¹ represents a lanthanoid element, scandium oryttrium; Cp^(R)s each independently represent unsubstituted/substitutedindenyl; R^(A) and R^(B) each independently represent a hydrocarbongroup having a carbon number of 1 to 20; M¹ and Al are μ-coordinatedwith R^(A) and R^(B); and R^(C) and R^(D) each independently represent ahydrocarbon group having a carbon number of 1 to 20 or a hydrogen atom.)

A targeted polymer can be manufactured by using the metallocene-basedpolymerization catalyst described above. Further, it is possible toreduce an amount of alkyl aluminum for use in the polymer synthesis oreven eliminate the alkyl aluminum by using the metallocene-basedcomposite catalyst described above, for example, a catalyst which hasbeen combined with aluminum catalyst in advance to be a composite. Itshould be noted in this connection that a large amount of alkyl aluminumis needed during the polymer synthesis if the conventional catalystsystem is employed. For example, alkyl aluminum must be used by anamount at least 10 times as much as the chemically equivalent amount ofa relevant metal catalyst in the conventional catalyst system. Incontrast, in the case of using the metallocene-based composite catalystdescribed above, a good catalytic effect is demonstrated by adding alkylaluminum by an amount around 5 times as much as the chemicallyequivalent amount of the metal catalyst.

With regard to the metallocene-based composite catalyst represented byformula (XIII), the metal M is a lanthanoid element, scandium oryttrium. The lanthanoid elements include the fifteen elements havingatomic numbers 57 to 71 and any of these elements is acceptable.Preferable examples of the core metal M include samarium Sm, neodymiumNd, praseodymium Pr, gadolinium Gd, cerium Ce, holmium Ho, scandium Sc,and yttrium Y.

In formula (XIII), Rs each independently representunsubstituted/substituted indenyl and M is coordinated with Rs. Specificexamples of the substituted indenyl group include 1,2,3-trimethylindenyl group, heptamethylindenyl group, 1,2,4,5,6,7-hexamethylindenylgroup, and the like.

In formula (XIII), Q represents a group 13 element in the periodic tableand specific examples thereof include boron, aluminum, gallium, indium,thallium, and the like.

In formula (XIII), Xs each independently represent a hydrocarbon grouphaving a carbon number of 1 to 20 and M and Q are μ-coordinated with X.Examples of the hydrocarbon group having a carbon number of 1 to 20include methyl group, ethyl group, propyl group, butyl group, pentylgroup, hexyl group, heptyl group, octyl group, decyl group, dodecylgroup, tridecyl group, tetradecyl group, pentadecyl group, hexadecylgroup, heptadecyl group, stearyl group, and the like. The expressionthat “M and Q are μ-coordinated with X” represents that M and Q arecoordinated with X in a crosslinking manner.

In formula (XIII), Ys each independently represent a hydrocarbon grouphaving a carbon number of 1 to 20 or a hydrogen atom and Q iscoordinated with Y. Examples of the hydrocarbon group having a carbonnumber of 1 to 20 include methyl group, ethyl group, propyl group, butylgroup, pentyl group, hexyl group, heptyl group, octyl group, decylgroup, dodecyl group, tridecyl group, tetradecyl group, pentadecylgroup, hexadecyl group, heptadecyl group, stearyl group, and the like.

In formula (XIV), the metal M¹ is a lanthanoid element, scandium oryttrium. The lanthanoid elements include the fifteen elements havingatomic numbers 57 to 71 and any of these elements is acceptable.Preferable examples of the core metal M¹ include samarium Sm, neodymiumNd, praseodymium Pr, gadolinium Gd, cerium Ce, holmium Ho, scandium Sc,and yttrium Y.

In formula (XIV), Cp^(R)s are unsubstituted/substituted indenyls. Cp^(R)having an indenyl ring as the base skeleton may be represented asC₉H_(7X)R_(X) or

C₉H_(11X)R_(X), wherein X is an integer in the range of 0 to 7 or 0 to11; Rs preferably each independently represent hydrocarbyl group ormetalloid group; and the carbon number of the hydrocarbyl group ispreferably in the range of 1 to 20, more preferably in the range of 1 to10, and even more preferably in the range of 1 to 8. Specifically,preferable examples of the hydrocarbyl group include methyl group, ethylgroup, phenyl group, benzyl group and the like. Examples of metalloid ofthe metalloid group include germyl Ge, stannyl Sn, and silyl Si. Themetalloid group preferably includes a hydrocarbyl group which is definedin the same manner as the aforementioned hydrocarbyl group. Specificexamples of the metalloid group include trimethylsilyl and the like.

Specific examples of the substituted indenyl include 2-phenylindenyl,2-methylindenyl, and the like. The two Cp^(R)s in formula (XIV) may beof either the same type or different types.

In formula (XIV), R^(A) and R^(B) each independently represent ahydrocarbon group having a carbon number of 1 to 20 and M¹ and Al arep.-coordinated with R^(A) and R^(B). Examples of the hydrocarbon grouphaving a carbon number of 1 to 20 include methyl group, ethyl group,propyl group, butyl group, pentyl group, hexyl group, heptyl group,octyl group, decyl group, dodecyl group, tridecyl group, tetradecylgroup, pentadecyl group, hexadecyl group, heptadecyl group, stearylgroup, and the like. The expression that “M and Q are μ-coordinated withX” represents that M and Q are coordinated with X in a crosslinkingmanner.

In formula (XIV), R^(C) and R^(D) each independently represent ahydrocarbon group having a carbon number of 1 to 20 or a hydrogen atom.Examples of the hydrocarbon group having a carbon number of 1 to 20include methyl group, ethyl group, propyl group, butyl group, pentylgroup, hexyl group, heptyl group, octyl group, decyl group, dodecylgroup, tridecyl group, tetradecyl group, pentadecyl group, hexadecylgroup, heptadecyl group, stearyl group, and the like.

The metallocene-based composite catalyst described above can be obtainedby reacting a metallocene complex represented by the following formula(XV) with an organic aluminum compound represented by AIR^(K)R^(L)R^(M)in a solvent.

(In formula (XV), M² represents a lanthanoid element, scandium oryttrium; Cp^(R)s each independently represent unsubstituted/substitutedindenyl; R^(E) to R^(J) each independently represent an alkyl grouphaving a carbon number of 1 to 3 or a hydrogen atom; L represents aneutral Lewis base; and w represents an integer in the range of 0 to 3).The reaction temperature may be set around the room temperature, whichallows production in a mild condition. The reaction time may be set asdesired and is generally in the range of a few hours to a few days. Typeof the reaction solvent is not particularly limited but preferably asolvent capable of dissolving the raw materials and a reaction product.For example, toluene or hexane can be used. The structure of themetallocene-based composite catalyst described above is preferablyobtained through ¹H-NMR or X-ray structural analysis.

In the metallocene complex represented by formula (XV), Cp^(R)s eachindependently represent unsubstituted/substituted indenyl and aredefined in the same manner as Cp^(R)s in formula (XIV); and the metal M²is a lanthanoid element, scandium or yttrium and defined in the samemanner as the metal M¹ in formula (XIV).

The metallocene complex represented by formula (XV) includes a silylamide ligand [—N(SiR₃)₂]. R groups included in the silyl amide ligand(i.e. R^(E) to R^(J)) each independently represent an alkyl group havinga carbon number of 1 to 3 or a hydrogen atom. It is preferable that atleast one of R^(E) to R^(J) is a hydrogen atom. The catalyst can beeasily synthesized when at least one of R^(E) to R^(J) is a hydrogenatom. For similar reasons, it is more preferable that at least one ofR^(E) to R^(G) is a hydrogen atom, and at least one of R^(H) to R^(J) isa hydrogen atom. Methyl group is preferable as the alkyl group.

The metallocene complex represented by formula (XV) further includes 0to 3, preferably 0 to 1, neutral Lewis base L. Examples of the neutralLewis base L include tetrahydrofuran, diethyl ether, dimethylaniline,trimethylphosphine, lithium chloride, neutral olefin, neutral diolefin,and the like. The neutral Lewis bases L may be of either the same typeor different types when the complex includes a plurality of neutralLewis bases L.

The metallocene complex represented by general formula (XV) may exist asany of monomer, dimer or another type of multimer.

The organic aluminum compound for use in generation of themetallocene-based composite catalyst described above is represented byAlR^(K)R^(L)R^(M), wherein R^(K) and R^(L) each independently representa monovalent hydrocarbon group having a carbon number of 1 to 20 or ahydrogen atom; R^(M) represents a monovalent hydrocarbon group having acarbon number of 1 to 20; and R^(M) may be of either the same type as ora different type from R^(K) and R^(L). Examples of the monovalenthydrocarbon group having a carbon number of 1 to 20 include methylgroup, ethyl group, propyl group, butyl group, pentyl group, hexylgroup, heptyl group, octyl group, decyl group, dodecyl group, tridecylgroup, tetradecyl group, pentadecyl group, hexadecyl group, heptadecylgroup, stearyl group, and the like.

Specific examples of the organic aluminum compound include trimethylaluminum, triethyl aluminum, tri-n-propyl aluminum, triisopropylaluminum, tri-n-butyl aluminum, triisobutyl aluminum, tri-t-butylaluminum, tripentyl aluminum, trihexyl aluminum, tricyclohexyl aluminum,trioctyl aluminum; diethyl aluminum hydride, di-n-propyl aluminumhydride, di-n-butyl aluminum hydride, diisobutyl aluminum hydride,dihexyl aluminum hydride, diisohexyl aluminum hydride, dioctyl aluminumhydride, diisooctyl aluminum hydride, ethyl aluminum dihydride, n-propylaluminum dihydride, isobutyl aluminum dihydride, and the like. Triethylaluminum, triisobutyl aluminum, diethyl aluminum hydride and diisobutylaluminum hydride are preferable as the organic aluminum compound amongthese examples. These organic aluminum compounds may be used singly orin a combination of two or more. An amount of the organic aluminumcompound for use in generation of the metallocene-based compositecatalyst is preferably 1 to 50 times, more preferably approximately 10times, as much as the amount of the metallocene complex when compared inmol.

The third polymerization catalyst composition may be composed of themetallocene-based composite catalyst described above and a boron anion.Further, the third polymerization catalyst composition preferably alsoincludes other components, e.g., a co-catalyst, contained in aconventional polymerization catalyst composition containing ametallocene-based catalyst. A catalyst composed of the metallocene-basedcomposite catalyst and a boron anion is occasionally referred to as a“two-component catalyst”. It is possible to control contents ofrespective polymer components in a resulting polymer as desired by usingthe third polymerization catalyst composition because the thirdpolymerization catalyst composition contains a boron anion, as well asthe metallocene-based composite catalyst.

Specific examples of the boron anion constituting a two-componentcatalyst as the third polymerization catalyst composition include aquadrivalent boron anion. Examples of the quadrivalent boron anioninclude tetraphenyl borate, tetrakis(monofluorophenyl)borate,tetrakis(difluorophenyl)borate, tetrakis(trifluorophenyl)borate,tetrakis(tetrafluorophenyl)borate, tetrakis(pentafluorophenyl)borate,tetrakis(tetrafluoromethylphenyl)borate, tetra(tolyl)borate,tetra(xylyl)borate, triphenyl(pentafluorophenyl)borate,[tris(pentafluorophenyl)](phenyl)borate,tridecahydride-7,8-dicarbaundecaborate, and the like.Tetrakis(pentafluorophenyl)borate is preferable as the quadrivalentboron anion among these examples.

The boron anion can be used as an ionic compound in which the boronanion is combined with a cation. Examples of the cation includecarbonium cation, oxonium cation, amine cation, phosphonium cation,cycloheptatrienyl cation, ferroceium cation having transition metal, andthe like. Specific examples of carbonium cation include trisubstitutedcarbonium cation such as triphenylcarbonium cation, tri(substitutedphenyl)carbonium cation, and the like. Specific examples of thetri(substituted phenyl)carbonium cation includetri(methylphenyl)carbonium cation, and the like. Specific examples ofthe amine cation include: trialkylammonium cation such astrimethylammonium cation, triethylammonium cation, tripropylammoniumcation, tributylammonium cation; N,N-dialkylanilinium cation such asN,N-dimethylanilinium cation, N,N-diethylanilinium cation,N,N-2,4,6-pentamethylanilinium cation, and the like; and dialkylammoniumcation such as diisopropylammonium cation, dicyclohexylammonium cation,and the like. Specific examples of phosphonium cation includetriarylphosphonium cation such as triphenylphosphonium cation,tri(methylphenyl)phosphonium cation, tri(dimethylphenyl)phosphoniumcation, and the like. N,N-dialkylanilinium cation and carbonium cationare preferable and N,N-dialkylanilinium cation is particularlypreferable as the cation among these examples. Accordingly,N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,triphenylcarbonium tetrakis(pentafluorophenyl)borate, and the like arepreferable as the ionic compound. The ionic compound composed of theboron anion and the cation is preferably added by an amount 0.1 to 10times, more preferably approximately 1 time, as much as the amount ofthe metallocene-based composite catalyst when compared in mol.

The metallocene-based composite catalyst represented by formula (XIV)cannot be synthesized when a boron anion exists in a reaction system forreacting a metallocene catalyst represented by formula (XV) with anorganic aluminum compound. Accordingly, preparation of the thirdpolymerization catalyst composition requires synthesizing themetallocene-based composite catalyst in advance, isolating and purifyingthe metallocene-based composite catalyst thus synthesized, and thencombining the metallocene-based composite catalyst with a boron anion.

Preferable examples of the co-catalyst which may be used for the thirdpolymerization catalyst composition include aluminoxane and the like, aswell as the aforementioned organic aluminum compound represented byMR^(K)R^(L)R^(m). Alkylaluminoxane is preferable as the aluminoxane andexamples thereof include methyl aluminoxane (MAO), modified methylaluminoxane, and the like. “MMAO-3A”, manufactured by Tosoh FinechemCorporation, or the like is preferable as the modified methylaluminoxane. The aluminoxanes may be used singly or in a combination oftwo or more.

<Coupling Process>

Coupling process is a process of carrying out a reaction (a couplingreaction) for modifying at least a portion, e.g., a terminal end, of apolymer chain of the multi-component copolymer obtained by thepolymerization process.

The coupling reaction of the coupling process is preferably carried outwhen the polymerization reaction reaches 100%.

Type of a coupling agent for use in the coupling reaction is notparticularly restricted and can be appropriately selected according tothe purpose. Examples of the coupling agent include: a tin-containingcompound such as bis(maleic acid-1-octadecyl)dioctyltin(IV); anisocyanate compound such as 4,4′-diphenylmethane diisocyanate; analkoxysilane compound such as glycidyl propyltrimethoxysilane; and thelike. These may be used singly or in a combination of two or more.

Bis(maleic acid-1-octadecyl)dioctyltin(IV) is preferable as the couplingagent among these examples in terms of high reaction efficiency andrelatively little gel generation.

The number average molecular weight (Mn) can be increased as a result ofcarrying out the coupling reaction.

<Rinsing Process>

Rinsing process is a process of rinsing a polymer composition obtainedby the aforementioned polymerization process. Examples of the solventinclude methanol, ethanol, isopropanol, and the like. An acid (such ashydrochloric acid, sulfuric acid, nitric acid) may be added to such asolvent as described above when the solvent is used for a polymerizationcatalyst composition blended with a Lewis acid-derived catalyst inparticular. An amount to be added, of the acid, is preferably 15 mol %or less with respect to the solvent. Addition of the acid by an amountexceeding 15 mol % with respect to the solvent may cause the acid toremain in polymer, possibly adversely affecting mixture, kneading and avulcanization reaction.

An amount of catalyst residue in copolymer can be decreased to anappropriate level by the rinsing process.

(Rubber Composition)

The rubber composition of this disclosure contains at least themulti-component copolymer of this disclosure, and may further contain,as necessary, a filler, a crosslinking agent, other components, or arubber component other than the multi-component copolymer of thisdisclosure. The rubber composition of this disclosure contains at leastthe multi-component copolymer of this disclosure, and thus has excellentlow heat generating property and rollability.

From the viewpoint of obtaining the desired effect more securely, thecontent of the multi-component copolymer of this disclosure in therubber composition of this disclosure is preferably 10 mass % or more,more preferably 20 mass % or more.

The rubber component other than the multi-component copolymer of thisdisclosure is not specifically limited and may be appropriately selecteddepending on the purpose. Examples include polyisoprene, butadienerubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber,ethylene-propylene rubber (EPM), ethylene-propylene-non-conjugated dienerubber (EPDM), polysulfide rubber, silicone rubber, fluororubber, andurethane rubber. These may be used singly or in a combination of two ormore.

The rubber composition may use a filler as necessary for the purpose ofimproving reinforcement or the like. The content of the filler is notlimited, and may be selected appropriately depending on the purpose;with respect to 100 parts by mass of rubber component, 10 parts by massto 100 parts by mass is preferable, 20 parts by mass to 80 parts by massis more preferable, and 30 parts by mass to 60 parts by mass isparticularly preferable. The filler compounded in an amount of 10 partsby mass or more provides an effect of improving reinforcement throughthe compounding of the filler, and the filler compounded in an amount of100 parts by mass or less can maintain favorable workability whileavoiding significant reduction in low heat generating property.

Examples of the filler may include, without being particularly limitedthereto, carbon black, silica, aluminum hydroxide, clay, alumina, talc,mica, kaolin, glass balloon, glass beads, calcium carbonate, magnesiumcarbonate, magnesium hydroxide, magnesium oxide, titanium oxide,potassium titanate, and barium sulfate, with the use of carbon blackbeing preferred. These may be used singly or in a combination of two ormore.

The carbon black is not particularly limited, and may be selected asappropriate depending on the application thereof. Examples thereofinclude FEF, GPF, SRF, HAF, N339, IISAF, ISAF, and SAF. These may beused singly or in a combination of two or more.

The nitrogen absorption specific surface area (N₂SA, measured accordingto JIS K 6217-2:2001) is not particularly limited and may be selected asappropriate depending on the intended use, which may preferably be 20 to100 m²/g, and more preferably 35 to 80 m²/g. The carbon black having thenitrogen absorption specific surface area (N₂SA) of 20 m²/g or moreimproves durability of the resulting rubber composition providingsufficient crack growth resistance, and the carbon black having thenitrogen absorption specific surface area (N₂SA) of 100 m²/g or less canmaintain favorable workability while avoiding significant reduction inlow heat generating property.

The rubber composition may use a crosslinking agent as necessary. Thecrosslinking agent may be selected as appropriate depending on theintended use, and the examples thereof may include, without beingparticularly limited, for example, a sulfur-based crosslinking agent, anorganic peroxide-based crosslinking agent, an inorganic crosslinkingagent, a polyamine crosslinking agent, a resin crosslinking agent, asulfur compound-based crosslinking agent, and an oxime-nitrosamine-basedcrosslinking agent, with the sulfur-based crosslinking agent(vulcanizing agent) being more preferred as the rubber composition foruse in tires.

The crosslinking agent above may be contained preferably in the range of0.1 to 20 parts by mass per 100 parts by mass of the rubber component,which may be selected as appropriate depending on the intended usewithout being particularly limited. Crosslinking may hardly beprogressed with the content of the crosslinking agent falling below 0.1parts by mass, whereas the content exceeding 20 parts by mass tends toallow some of the crosslinking agent to inadvertently promotecrosslinking during the kneading, which may also impair the physicalproperty of the vulcanized product.

When using the vulcanizing agent, vulcanization accelerators mayadditionally be used in combination. Examples of the vulcanizationaccelerators may include a guanidine-based compound, analdehyde-amine-based compound, an aldehyde-ammonia-based compound, athiazole-based compound, a sulfenamide-based compound, a thiourea-basedcompound, a thiuram-based compound, a dithiocarbamate-based compound,and a xanthate-based compound. Further, the rubber composition of thisdisclosure may use, as necessary depending on the intended use, asoftener, a vulcanization aid, a colorant, a flame retarder, alubricant, a foaming agent, a plasticizer, a processing aid, anantioxidant, an age resistor, an antiscorching agent, ananti-ultraviolet agent, an antistatic agent, and other publicly-knowncompounding agents.

(Crosslinked Rubber Composition)

The crosslinked rubber composition of this disclosure is a crosslinkedproduct of the aforementioned rubber composition of this disclosure. Thecrosslinked rubber composition of this disclosure is derived from themulti-component copolymer of this disclosure, and thus is easy tomanufacture and has excellent low heat generating property. Thecrosslinking conditions are not particularly limited and may be selectedas appropriate depending on the purpose, and the crosslinking may beperformed preferably at a temperature of 120° C. to 200° C. over awarming time of 1 minute to 900 minutes. The crosslinked rubbercomposition thus obtained, which does not use a non-conjugated dienecompound as a monomer from which the rubber component is derived, isexcellent in crosslinking property and thus has a higher mechanicalproperty, as compared with a case of EPDM which uses a polymer having anon-conjugated diene compound as a monomer thereof.

(Rubber Article)

The rubber article of this disclosure uses the crosslinked rubbercomposition of this disclosure. The rubber article of this disclosurecontains a crosslinked product of the rubber composition containing themulti-component copolymer of this disclosure, and thus is easy tomanufacture and has excellent low heat generating property. Type andmanufacture method of the rubber article of this disclosure is notspecifically limited and may be appropriately selected depending on thepurpose. Examples of the “rubber article” include tires, anti-vibrationrubbers, seismic isolation rubbers, belts such as conveyor belts, rubbercrawlers, and various hoses. The disclosed rubber composition may beapplied to any part of the tire with no particular limitation, which maybe selected as appropriate depending on the intended use, such as treadrubber, cap tread rubber, base tread rubber, sidewall rubber, sidereinforcing rubber, bead and bead filler. Among these, from theviewpoint of effectively improving the low heat generating property ofthe tire, the crosslinked rubber composition of this disclosure ispreferably used to tread rubber and cap tread rubber.

EXAMPLES

In the following, the present disclosure is described in detail withreference to Examples. However, the present disclosure is no way limitedto Examples in below.

Synthesis Example 1: Copolymer A

300 g of a cyclohexane solution containing 150 g (1.92 mol) of styrenewas added to a 2 L stainless steel reactor that had been sufficientlydried. Meanwhile, in a glovebox under a nitrogen atmosphere, 273 μmol of1,3-bis(t-butyldimethysilyl)indenyl gadoliniumbis(bis(dimethylsilyl)amide) [1,3-(t-BuMe₂Si)₂C₉H₅Gd(N(SiHMe₂)₂)₂], 300μmol of dimethylanilinium tetrakis(pentafluorophenyl)borate[Me₂NHPhB(C₆F₅)₄], and 3.60 mmol of diisobutyl aluminum hydride werecharged in a glass container, and dissolved with 180 mL of cyclohexane,to thereby obtain a catalyst solution. After that, the catalyst solutionwas taken out from the glovebox and added in the total amount to themonomer solution, before introducing 150 g of a monomer solutioncontaining 35 g (0.64 mol) of 1,3-butadiene, which was then subjected topolymerization at 70° C. for 320 minutes under ethylene pressure (1.5MPa). After the polymerization, 1 mL of an isopropanol solutioncontaining, by 5 mass %, 2,2′-methylene-bis(4-ethyl-6-t-butylphenol)(NS-5), was added to stop the reaction. Then, a large amount of2-propanol was further added to isolate the copolymer, and the copolymerwas vacuum dried at 60° C. to obtain a copolymer A. Thereby, a polymer Awas obtained, and a yield thereof was 184 g.

Synthesis Example 2: Copolymer B

200 g of a cyclohexane solution containing 60 g (0.57 mol) of styrenewas added to a 2 L stainless steel reactor that had been sufficientlydried. Meanwhile, in a glovebox under a nitrogen atmosphere, 120 μmol of1,3-bis(t-butyldimethysilyl)indenyl gadoliniumbis(bis(dimethylsilyl)amide) [1,3-(t-BuMe₂Si)₂C₉H₅Gd(N(SiHMe₂)₂)₂], 132μmol of dimethylanilinium tetrakis(pentafluorophenyl)borate[Me₂NHPhB(C₆F₅)₄], and 2.70 mmol of diisobutyl aluminum hydride werecharged in a glass container, and dissolved with 90 mL of cyclohexane,to thereby obtain a catalyst solution. After that, the catalyst solutionwas taken out from the glovebox and added in the total amount to themonomer solution, before introducing 220 g of a monomer solutioncontaining 70 g (1.29 mol) of 1,3-butadiene, which was then subjected topolymerization at 70° C. for 270 minutes under ethylene pressure (1.5MPa). After the polymerization, 1 mL of an isopropanol solutioncontaining, by 5 mass %, 2,2′-methylene-bis(4-ethyl-6-t-butylphenol)(NS-5), was added to stop the reaction. Then, a large amount of2-propanol was further added to isolate the copolymer, and the copolymerwas vacuum dried at 60° C. to obtain a copolymer B. Thereby, a polymer Bwas obtained, and a yield thereof was 128 g.

Synthesis Example 3: Copolymer C

220 g of a toluene solution containing 55 g (0.52 mol) of styrene wasadded to a 2 L stainless steel reactor that had been sufficiently dried.Meanwhile, in a glovebox under a nitrogen atmosphere, 100 μmol of1,3-bis(t-butyldimethysilyl)indenyl gadoliniumbis(bis(dimethylsilyl)amide) [1,3-(t-BuMe₂Si)₂C₉H₅Gd(N(SiHMe₂)₂)₂], 110μmol of dimethylanilinium tetrakis(pentafluorophenyl)borate[Me₂NHPhB(C₆F₅)₄], and 2.90 mmol of diisobutyl aluminum hydride werecharged in a glass container, and dissolved with 90 mL of cyclohexane,to thereby obtain a catalyst solution. After that, the catalyst solutionwas taken out from the glovebox and added in the total amount to themonomer solution, before introducing 300 g of a monomer solutioncontaining 75 g (1.38 mol) of 1,3-butadiene, which was then subjected topolymerization at 70° C. for 320 minutes under ethylene pressure (1.5MPa). After the polymerization, 1 mL of an isopropanol solutioncontaining, by 5 mass %, 2,2′-methylene-bis(4-ethyl-6-t-butylphenol)(NS-5), was added to stop the reaction. Then, a large amount of2-propanol was further added to isolate the copolymer, and the copolymerwas vacuum dried at 60° C. to obtain a copolymer C. Thereby, a polymer Cwas obtained, and a yield thereof was 148 g.

Synthesis Example 4: Copolymer D

200 g of a cyclohexane solution containing 90 g (0.86 mol) of styrenewas added to a 2 L stainless steel reactor that had been sufficientlydried. Meanwhile, in a glovebox under a nitrogen atmosphere, 260 μmol of1,3-bis(t-butyldimethysilyl)indenyl gadoliniumbis(bis(dimethylsilyl)amide) [1,3-(t-BuMe₂Si)₂C₉H₅Gd(N(SiHMe₂)₂)₂], 286μmol of dimethylanilinium tetrakis(pentafluorophenyl)borate[Me₂NHPhB(C₆F₅)₄], and 2.85 mmol of diisobutyl aluminum hydride werecharged in a glass container, and dissolved with 165 mL of cyclohexane,to thereby obtain a catalyst solution. After that, the catalyst solutionwas taken out from the glovebox and added in the total amount to themonomer solution, before introducing 200 g of a monomer solutioncontaining 50 g (0.92 mol) of 1,3-butadiene, which was then subjected topolymerization at 70° C. for 420 minutes under ethylene pressure (1.5MPa). After the polymerization, 1 mL of an isopropanol solutioncontaining, by 5 mass %, 2,2′-methylene-bis(4-ethyl-6-t-butylphenol)(NS-5), was added to stop the reaction. Then, a large amount of2-propanol was further added to isolate the copolymer, and the copolymerwas vacuum dried at 60° C. to obtain a copolymer D. Thereby, a polymer Dwas obtained, and a yield thereof was 140 g.

Synthesis Example 5: Copolymer a

150 g of a cyclohexane solution containing 30 g (0.28 mol) of styrenewas added to a 2 L stainless steel reactor that had been sufficientlydried. Meanwhile, in a glovebox under a nitrogen atmosphere, 120 μmol of1,3-bis(t-butyldimethysilyl)indenyl gadoliniumbis(bis(dimethylsilyl)amide) [1,3-(t-BuMe₂Si)₂C₉H₅Gd(N(SiHMe₂)₂)₂], 132μmol of dimethylanilinium tetrakis(pentafluorophenyl)borate[Me₂NHPhB(C₆F₅)₄], and 1.68 mmol of diisobutyl aluminum hydride werecharged in a glass container, and dissolved with 100 mL of cyclohexane,to thereby obtain a catalyst solution. After that, the catalyst solutionwas taken out from the glovebox and added in the total amount to themonomer solution, before introducing 120 g of a monomer solutioncontaining 15 g (0.27 mol) of 1,3-butadiene, which was then subjected topolymerization at 80° C. for 90 minutes under ethylene pressure (0.5MPa). After the polymerization, 1 mL of an isopropanol solutioncontaining, by 5 mass %, 2,2′-methylene-bis(4-ethyl-6-t-butylphenol)(NS-5), was added to stop the reaction. Then, a large amount of2-propanol was further added to isolate the copolymer, and the copolymerwas vacuum dried at 60° C. to obtain a copolymer a. Thereby, a polymer awas obtained, and a yield thereof was 40 g.

Synthesis Example 6: Copolymer b

150 g of a cyclohexane solution containing 90 g (0.28 mol) of styrenewas added to a 2 L stainless steel reactor that had been sufficientlydried. Meanwhile, in a glovebox under a nitrogen atmosphere, 240 μmol of1,3-bis(t-butyldimethysilyl)indenyl gadoliniumbis(bis(dimethylsilyl)amide) [1,3-(t-BuMe₂Si)₂C₉H₅Gd(N(SiHMe₂)₂)₂], 3.10mmol of diisobutyl aluminum hydride, and 264 μmol of dimethylaniliniumtetrakis(pentafluorophenyl)borate [Me₂NHPhB(C₆F₅)₄] were charged in aglass container, and dissolved with 60 mL of cyclohexane, to therebyobtain a catalyst solution. After that, the catalyst solution was takenout from the glovebox and added in the total amount to the reactor,before introducing 180 g of a monomer solution containing 65 g (1.20mol) of 1,3-butadiene, which was then subjected to polymerization at 70°C. for 200 minutes under ethylene pressure (0.5 MPa). After thepolymerization, 2 mL of a 2-propanol solution containing, by 5 mass %,2,2′-methylene-bis(4-ethyl-6-t-butylphenol) (NS-5), was added to stopthe reaction. Then, a large amount of 2-propanol was further added toisolate the copolymer, and the copolymer was vacuum dried at 60° C. toobtain a copolymer b. Thereby, a polymer b was obtained, and a yieldthereof was 165 g.

(Preparation of Copolymer c)

A styrene-butadiene copolymer (product name: #1502), manufactured by JSRCorporation, was prepared as a copolymer c.

(Identification of Multicomponent Copolymer)

First, each of the copolymers obtained as described above was measuredfor a gel permeation chromatography-refractive ratio curve (GPC-RIcurve) to confirm whether the copolymer was monodisperse, and thenmeasured for ¹H-NMR spectrum and ¹³C-NMR spectrum to confirm an aromaticring skeleton derived from an aromatic vinyl compound, in order toconfirm characteristic peaks derived from each monomer.

In this way, copolymers A to D and a to b were confirmed astricopolymers.

Next, regarding each copolymer the polystyrene equivalent weight-averagemolecular weight (Mw), the molecular weight distribution (Mw/Mn), themicrostructure, and the ratio among all of the aromatic vinyl units ofat least one aromatic vinyl unit existing in amorphous parts inclusiveof the conjugated diene units were measured and evaluated with thefollowing methods. The result was as indicated in Table 1.

<Polystyrene Equivalent Weight-Average Molecular Weight (Mw) andMolecular Weight Distribution (Mw/Mn)>

A polystyrene equivalent weight-average molecular weight (MW) and amolecular weight distribution (Mw/Mn) of each of the copolymers wereobtained through gel permeation chromatography [GPC: HLC-8321GPC/HT(manufactured by Tosoh Corporation), column: two of GMH_(HR)-H(S)HT(manufactured by Tosoh Corporation), detector: a differentialrefractometer (RI)], using monodisperse polystyrene as a reference andtrichlorobenzene as a solvent. The measurement temperature was 140° C.

<Microstructure>

A microstructure of each of the copolymers was obtained based on, forexample, an integration ratio of the ¹H-NMR spectrum (1,2-vinyl bondcontent) and the ¹³C-NMR spectrum (the content ratio of cis-1,4 bond andtrans-1,4 bond). Table 1 indicates the cis-1,4 bond content (%), thetrans-1,4 bond content (%) and the 1,2 vinyl bond content (%) among allof the conjugated diene units, the content (mol %) of the conjugateddiene units, the content (mol %) of the non-conjugated olefin units, andthe content (mol %) of the aromatic vinyl units.

For example, regarding copolymer A, a molar ratio of ethylene units(Et)/butadiene units (Bd)/styrene units (St) was calculated as followingfrom a peak integral value of 6.75 ppm to 7.50 ppm, and a sum of anintegral value of 0.50 ppm to 1.75 ppm, an integral value of 4.75 ppm to5.10 ppm and an integral value of 5.20 ppm to 5.50 ppm of the measured¹H-NMR spectrum.Et:Bd:St=1.62/4:(0.01+0.10)/2:1.0/5=55:18:27

<Ratio of Aromatic Vinyl Units Existing in Amorphous Parts Inclusive ofConjugated Diene Units Among all Aromatic Vinyl Units>

A ratio (A) of the non-conjugated olefin units and the aromatic vinylunits in the multi-component copolymer was obtained from an integrationratio of the ¹H-NMR spectrum and the ¹³C-NMR spectrum, and then, thediene parts contained in the multi-component copolymer was ozonolyzed,and a ratio (B) of the non-conjugated olefin units and the aromaticvinyl units in the entire obtained component exclusive of the dieneparts (the component consisting of the non-conjugated olefin unitsand/or the aromatic vinyl units) from an integration ratio of the ¹H-NMRspectrum and the ¹³C-NMR spectrum. The ratio among all of the aromaticvinyl units of at least one aromatic vinyl unit existing in theamorphous parts inclusive of conjugated diene units was obtained byusing the ratio (A) and the ratio (B).

(Preparation and Evaluation of Rubber Composition)

Rubber compositions were prepared by using each copolymer according tothe formulations as indicated in Table 2, with a conventional method.This rubber composition was measured of the rollability according to thefollowing method. Next, each of the rubber compositions was crosslinked(vulcanized) at 160° C. for 30 minutes to obtain a crosslinked rubbercomposition, and this crosslinked rubber composition was measured of thelow heat generating property with the following methods. The result wasas indicated in Table 2.

(Rollability)

Unvulcanized rubber formulations were wound around a 6-inch open roll at60° C., and the respective winding states were visually observed toevaluate their rollability, the results of which were classified intothe following three ratings:

Excellent: adhered to the roll upon entry; showing good rollability.

Good: wound around the roll upon entry; workable.

Poor: non-adhesive, failed to be wound around the roll; unrollable

<Low Heat Generating Property>

A loss tangent (tan δ) was measured by using a dynamic Spectrometer(manufactured by Rheometrics Inc. of the United States), under theconditions of tensile dynamic strain: 10%, frequency: 15 Hz,temperature: 50° C. The tan δ of each example was indexed with the tan δof Comparative Example 3 using a styrene-butadiene copolymer as a rubbercomponent as 100. A smaller index value indicates better low heatgenerating property (low loss property).

TABLE 1 Copolymer Copolymer Copolymer Copolymer Copolymer CopolymerCopolymer A B C D a b c Content of aromatic vinyl units [mol %] 27 19 1431 26 19 14 Content of non-conjugated olefin units [mol %] 55 25 40 3025 45 0 Content of conjugated diene units [mol %] 18 56 46 39 49 36 86Content of cis-1,4 bond [%] 78.3 86.2 85.1 83.9 89.6 85.4 Not Content oftrans-1,4 bond [%] 16.6 9.2 11.1 13.4 7.6 11 measured Content of1,2-vinyl bond [%] 5.1 4.6 3.8 2.7 2.8 3.6 Polystyrene equivalentweight-average 419,000 398,000 411,000 444,000 358,000 390,000 molecularweight (Mw) Molecular weight distribution (Mw/Mn) 3.91 3.65 4.18 3.313.28 3.99 Ratio among all aromatic vinyl units of [%] 5 45 30 12 55 76 —aromatic vinyl units existing in amorphous parts containing conjugateddiene units

TABLE 2 (Unit: parts by mass) Comparative Comparative ComparativeExample 1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3Copolymer A 100 0 0 0 0 0 0 Copolymer B 0 100 0 0 0 0 0 Copolymer C 0 0100 0 0 0 0 Copolymer D 0 0 0 100 0 0 0 Copolymer a 0 0 0 0 100 0 0Copolymer b 0 0 0 0 0 100 0 Copolymer c 0 0 0 0 0 0 100 Carbon black*150 50 50 50 50 50 50 Stearic acid 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Ageresistor*2 1 1 1 1 1 1 1 Wax*3 2 2 2 2 2 2 2 Oil*4 10 10 10 10 10 10 10Zinc oxide 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Vulcanization accelerator A*5 1.01.0 1.0 1.0 1.0 1.0 1.0 Vulcanization accelerator B*6 0.5 0.5 0.5 0.50.5 0.5 0.5 Vulcanization accelerator C*7 0.5 0.5 0.5 0.5 0.5 0.5 0.5Sulfur 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Low heat generating property 89 98 9095 109 115 100 Rollability Excellent Excellent Excellent xcellent GoodPoor Excellent *1Carbon black: “#75NP”, manufactured by Asahi CarbonCo., Ltd., HAF grade, nitrogen absorption specific surface area: 78 m²/g*2Age resistor: “NOCRAC 6C”, manufactured by Ouchi Shinko ChemicalIndustrial Co., Ltd. *3Wax: “SUNTIGHT A”, manufactured by Seiko-ChemicalCo., Ltd. *4Oil: “JOMO PROCESS NC300BN”, manufactured by JX Nippon Oil &Energy Corporation *5Vulcanization accelerator A: “NOCCELER D”,manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.*6Vulcanization accelerator B: “NOCCELER DM-P”, manufactured by OuchiShinko Chemical Industrial Co., Ltd. *7Vulcanization accelerator C:“NOCCELER NS-P”, manufactured by Ouchi Shinko Chemical Industrial Co.,Ltd.

According to Tables 1 and 2, it is understood that the copolymers thathave conjugated diene units, non-conjugated olefin units and aromaticvinyl units and have a ratio of at least one aromatic vinyl unitexisting in amorphous parts inclusive of the conjugated diene unitsamong all of the aromatic vinyl units of less than 50%, and the rubbercomposition of Examples 1 to 4 respectively containing the copolymers,have excellent low heat generating property and rollability.

INDUSTRIAL APPLICABILITY

According to this disclosure, it is possible to provide amulti-component copolymer capable of improving the rollability of arubber composition while having excellent low heat generating property.Moreover, according to this disclosure, it is possible to provide arubber composition having excellent low heat generating property androllability. Furthermore, according to this disclosure, it is possibleto provide a crosslinked rubber composition and a rubber article usingthe aforementioned rubber composition, which are easy to manufacture andhave excellent low heat generating property.

The invention claimed is:
 1. A multi-component copolymer comprisingconjugated diene units, non-conjugated olefin units and aromatic vinylunits, wherein: the multi-component copolymer is a terpolymer consistingexclusively of 1,3-butadiene units as the conjugated diene units,ethylene units as the non-conjugated olefin units, and styrene units asthe aromatic vinyl units, a ratio among all of the aromatic vinyl unitsof at least one aromatic vinyl unit existing in amorphous partsinclusive of the conjugated diene units is less than 50%, the ratiobeing obtained by using a ratio (A) of the non-conjugated olefin unitsand the aromatic vinyl units in the multi-component copolymer, which isobtained from an integration ratio of the ¹H-NMR spectrum, and a ratio(B) of the non-conjugated olefin units and the aromatic vinyl units in acomponent exclusive of the diene parts which is obtained afterozonolyzing the diene parts contained in the multicomponent copolymer,which is obtained from an integration ratio of the ¹H-NMR spectrum, andthe multi-component copolymer has a polystyrene equivalentweight-average molecular weight (Mw) of 100,000 to 9,000,000.
 2. Themulti-component copolymer according to claim 1, wherein: a cis-1,4 bondcontent among all of the conjugated diene units is 50% or more.
 3. Themulti-component copolymer according to claim 1, wherein: a content ofthe aromatic vinyl units is 2 mol % or more.
 4. The multi-componentcopolymer according to claim 1, wherein: the content of the aromaticvinyl units is 30 mol % or less.
 5. The multi-component copolymeraccording to claim 1, wherein: a content of the conjugated diene unitsis 15 mol % or more.
 6. The multi-component copolymer according to claim1, wherein: the content of the conjugated diene units is 60 mol % orless.
 7. The multi-component copolymer according to claim 1, wherein: acontent of the non-conjugated olefin units is 25 mol % or more.
 8. Themulti-component copolymer according to claim 1, wherein: the content ofthe non-conjugated olefin units is 80 mol % or less.
 9. Themulti-component copolymer according to claim 1, wherein: the aromaticvinyl units comprise styrene units.
 10. The multi-component copolymeraccording to claim 1, wherein: the conjugated diene units comprise1,3-butadiene units and/or isoprene units.
 11. A rubber compositioncomprising the multi-component copolymer according to claim
 1. 12. Acrosslinked rubber composition being a crosslinked product of the rubbercomposition according to claim
 11. 13. A rubber article comprising thecrosslinked rubber composition according to claim
 12. 14. The rubberarticle according to claim 13, being a tire.
 15. The multi-componentcopolymer according to claim 2, wherein: a content of the aromatic vinylunits is 2 mol % or more.
 16. The multi-component copolymer according toclaim 2, wherein: the content of the aromatic vinyl units is 30 mol % orless.
 17. The multi-component copolymer according to claim 2, wherein: acontent of the conjugated diene units is 15 mol % or more.
 18. Themulti-component copolymer according to claim 1, having a molecularweight distribution (Mw/Mn) represented by the ratio of the polystyreneequivalent weight-average molecular weight (Mw) to a polystyreneequivalent number-average molecular weight (Mn) of 3.31 or more and 10.0or less.